Colin Gordon, University of Iowa

Republicans in the U.S. Senate are sparring over their version of the multitrillion-dollar budget and immigration bill the House of Representatives passed on May 22, 2025.

Some GOP senators are insisting on shrinking the budget deficit, which the House version would increase by about US$3.8 trillion over a decade.

Others are saying they oppose the House’s cost-cutting provisions for Medicaid, the government’s health insurance program for people who are low income or have disabilities.

Despite the calls from U.S. Sen. Josh Hawley of Missouri and a few other Republican senators to protect Medicaid, as a scholar of American social policy I’m expecting to see the Senate embrace the introduction of work requirements for many adults under 65 who get health insurance through the program.

The House version calls for the states, which administer Medicaid within their borders and help pay for the program, to adopt work requirements by the end of 2026. The effect of this policy, animated by the conviction that coverage is too generous and too easy to obtain, will be to deny Medicaid eligibility to millions of those currently covered – leaving them without access to basic health services, including preventive care and the management of ongoing conditions such as asthma or diabetes.

Ending welfare

The notion that people who get government benefits should prove that they deserve them, ideally through paid labor, is now centuries old. This conviction underlay the Victorian workhouses in 19th-century England that Charles Dickens critiqued through his novels.

U.S. Rep. Brett Guthrie, R-Ky., put it bluntly earlier this month: Medicaid is “subsidizing capable adults who choose not to work,” he said.

This idea also animated the development of the American welfare state, from its origins in the 1930s organized around the goals of maintaining civil order and compelling paid labor. Enforcing work obligations ensured the ready availability of low-wage labor and supported the growing assumption that only paid labor could redeem the lives and aspirations of the poor.

“We started offering hope and opportunity along with the welfare check,” Wisconsin Gov. Tommy Thompson argued in the early 1990s, “and expecting certain responsibilities in return.”

This concept also was at the heart of the U.S. government’s bid to end “welfare as we know it.”

In 1996, the Democratic Clinton administration replaced Aid to Families with Dependent Children, or AFDC, a long-standing entitlement to cash assistance for low-income families, with Temporary Aid for Needy Families, known commonly as TANF. The TANF program, as its name indicates, was limited to short-term support, with the expectation that most people getting these benefits would soon gain long-term employment.

Since 1996, Republicans serving at the state and federal levels of government have pressed to extend this principle to other programs that help low-income people. They’ve insisted, as President Donald Trump put it halfway through his first term, that unconditional benefits have “delayed economic independence, perpetuated poverty, and weakened family bonds.”

Such claims are unsupported. There is no evidence to suggest that work requirements have ever galvanized independence or lifted low-income people out of poverty. Instead, they have punished low-income people by denying them the benefits or assistance they require.

Work requirements haven’t worked

Work requirements have consistently failed as a spur to employment. The transition from the AFDC to TANF required low-income families to meet work requirements, new administrative burdens and punitive sanctions.

The new work expectations, rolled out in 1997, were not accompanied by supporting policies, especially the child care subsidies that many low-income parents with young children require to hold a job. They were also at odds with the very low-paying and unstable jobs available to those transitioning from welfare.

Scholars found that TANF did less to lift families out of poverty than it did to shuffle its burden, helping the nearly poor at the expense of the very poor.

The program took an especially large toll on low-income Black women, as work requirements exposed recipients to long-standing patterns of racial and gender discrimination in private labor markets.

Restricting access to SNAP

Work requirements tied to other government programs have similar track records.

The Supplemental Nutrition Assistance Program, which helps millions of Americans buy groceries, adopted work requirements for able-bodied adults in 1996.

Researchers have found that SNAP’s work requirements have pared back eligibility without any measurable increase in labor force participation.

As happens with TANF, most people with SNAP benefits who have to comply with SNAP work requirements are already working to the degree their personal circumstances and local labor markets allow.

The requirements don’t encourage SNAP recipients to work more hours; they simply lead people to be overwhelmed by red tape and stop renewing their SNAP benefits.

Failing in Arkansas

The logic of work requirements collapses entirely when extended to Medicaid.

Red states have been pressing for years for waivers that would allow them to experiment with work requirements – especially for the abled-bodied, working-age adults who gained coverage under the Affordable Care Act’s Medicaid expansion.

The first Trump administration granted 13 such waivers for what it saw as “meritorious innovations,” building “on the human dignity that comes with training, employment and independence.”

Arkansas got the furthest with adding work requirements to Medicaid at that time. The results were disappointing.

“We found no evidence that the policy succeeded in its stated goal of promoting work,” as one research team concluded, “and instead found substantial evidence of harm to health care coverage and access.”

The Biden administration slowed down the implementation of these waivers by directing the Centers for Medicare and Medicaid Services to suspend or stem any state programs that eroded coverage. Meanwhile, state courts consistently ruled against the use of Medicaid work requirements.

In Trump’s second term, Iowa, Arizona and at least a dozen other states have proposed “work requirement” waivers for federal approval.

Trying it again

The waiver process is meant to allow state experiments to further the statutory objectives of the Medicaid program, which is to furnish “medical assistance on behalf of families with dependent children and of aged, blind, or disabled individuals, whose income and resources are insufficient to meet the costs of necessary medical services.”

On these grounds, the courts have consistently held that state waivers imposing work requirements not only fail to promote Medicaid’s objectives but amount to an arbitrary and capricious effort to undermine those objectives.

“The text of the statute includes one primary purpose,” the D.C. Circuit ruled in 2020, “which is providing health care coverage without any restriction geared to healthy outcomes, financial independence or transition to commercial coverage.”

Changing Medicaid in all states

The House spending bill includes a work requirement that would require all able-bodied, childless adults under 65 to demonstrate that they had worked, volunteered or participated in job training for 80 hours in the month before enrollment.

It would also allow states to extend such work requirements to six months and apply the new requirements not just to Medicaid recipients but to people who get subsidized health insurance through an Affordable Care Act exchange.

If passed in some form by the Senate, the House spending bill would transform the landscape of Medicaid work requirements, pushing an estimated 4.8 million Americans into the ranks of the uninsured.

Colin Gordon, Professor of History, University of Iowa

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bill Sullivan, Indiana University

Male fertility rates have been plummeting over the past half-century. An analysis from 1992 noted a steady decrease in sperm counts and quality since the 1940s. A more recent study found that male infertility rates increased nearly 80% from 1990 to 2019. The reasons driving this trend remain a mystery, but frequently cited culprits include obesity, poor diet and environmental toxins.

Infectious diseases such as gonorrhea or chlamydia are often overlooked factors that affect fertility in men. Accumulating evidence suggests that a common single-celled parasite called Toxoplasma gondii may also be a contributor: An April 2025 study showed for the first time that “human sperm lose their heads upon direct contact” with the parasite.

I am a microbiologist, and my lab studies Toxoplasma. This new study bolsters emerging findings that underscore the importance of preventing this parasitic infection.

The many ways you can get toxoplasmosis

Infected cats defecate Toxoplasma eggs into the litter box, garden or other places in the environment where they can be picked up by humans or other animals. Water, shellfish and unwashed fruits and vegetables can also harbor infectious parasite eggs.

In addition to eggs, tissue cysts present in the meat of warm-blooded animals can spread toxoplasmosis as well if they are not destroyed by cooking to proper temperature.

While most hosts of the parasite can control the initial infection with few if any symptoms, Toxoplasma remains in the body for life as dormant cysts in brain, heart and muscle tissue. These cysts can reactivate and cause additional episodes of severe illness that damage critical organ systems.

Between 30% and 50% of the world’s population is permanently infected with Toxoplasma due to the many ways the parasite can spread.

Toxoplasma can target male reproductive organs

Upon infection, Toxoplasma spreads to virtually every organ and skeletal muscle. Evidence that Toxoplasma can also target human male reproductive organs first surfaced during the height of the AIDS pandemic in the 1980s, when some patients presented with the parasitic infection in their testes.

While immunocompromised patients are most at risk for testicular toxoplasmosis, it can also occur in otherwise healthy individuals. Imaging studies of infected mice confirm that Toxoplasma parasites quickly travel to the testes in addition to the brain and eyes within days of infection.

In 2017, my colleagues and I found that Toxoplasma can also form cysts in mouse prostates. Researchers have also observed these parasites in the ejaculate of many animals, including human semen, raising the possibility of sexual transmission.

Knowing that Toxoplasma can reside in male reproductive organs has prompted analyses of fertility in infected men. A small 2021 study in Prague of 163 men infected with Toxoplasma found that over 86% had semen anomalies.

A 2002 study in China found that infertile couples are more likely to have a Toxoplasma infection than fertile couples, 34.83% versus 12.11%. A 2005 study in China also found that sterile men are more likely to test positive for Toxoplasma than fertile men.

Not all studies, however, produce a link between toxoplasmosis and sperm quality.

Toxoplasma can directly damage human sperm

Toxoplasmosis in animals mirrors infection in humans, which allows researchers to address questions that are not easy to examine in people.

Testicular function and sperm production are sharply diminished in Toxoplasma-infected mice, rats and rams. Infected mice have significantly lower sperm counts and a higher proportion of abnormally shaped sperm.

In that April 2025 study, researchers from Germany, Uruguay and Chile observed that Toxoplasma can reach the testes and epididymis, the tube where sperm mature and are stored, two days after infection in mice. This finding prompted the team to test what happens when the parasite comes into direct contact with human sperm in a test tube.

After only five minutes of exposure to the parasite, 22.4% of sperm cells were beheaded. The number of decapitated sperm increased the longer they interacted with the parasites. Sperm cells that maintained their head were often twisted and misshapen. Some sperm cells had holes in their head, suggesting the parasites were trying to invade them as it would any other type of cell in the organs it infiltrates.

In addition to direct contact, Toxoplasma may also damage sperm because the infection promotes chronic inflammation. Inflammatory conditions in the male reproductive tract are harmful to sperm production and function.

The researchers speculate that the harmful effects Toxoplasma may have on sperm could be contributing to large global declines in male fertility over the past decades.

Preventing toxoplasmosis

The evidence that Toxoplasma can infiltrate male reproductive organs in animals is compelling, but whether this produces health issues in people remains unclear. Testicular toxoplasmosis shows that parasites can invade human testes, but symptomatic disease is very rare. Studies to date that show defects in the sperm of infected men are too small to draw firm conclusions at this time.

Additionally, some reports suggest that rates of toxoplasmosis in high-income countries have not been increasing over the past few decades while male infertility was rising, so it’s likely to only be one part of the puzzle.

Regardless of this parasite’s potential effect on fertility, it is wise to avoid Toxoplasma. An infection can cause miscarriage or birth defects if someone acquires it for the first time during pregnancy, and it can be life-threatening for immunocompromised people. Toxoplasma is also the leading cause of death from foodborne illness in the United States.

Taking proper care of your cat, promptly cleaning the litter box and thoroughly washing your hands after can help reduce your exposure to Toxoplasma. You can also protect yourself from this parasite by washing fruits and vegetables, cooking meat to proper temperatures before consuming and avoiding raw shellfish, raw water and raw milk.

Bill Sullivan, Professor of Microbiology and Immunology, Indiana University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sofia Marie Haley, University of Nevada, Reno

I approach a flock of mountain chickadees feasting on pine nuts. A cacophony of sounds, coming from the many different bird species that rely on the Sierra Nevada’s diverse pine cone crop, fill the crisp mountain air.

The strong “chick-a-dee” call sticks out among the bird vocalizations. The chickadees are communicating to each other about food sources – and my approach.

Mountain chickadees are a member of the family Paridae, which is known for its complex vocal communication systems and cognitive abilities. Along with my advisers, behavioral ecologists Vladimir Pravosudov and Carrie Branch, I’m studying mountain chickadees at our study site in Sagehen Experimental Forest, outside of Truckee, California, for my doctoral research. I am focusing on how these birds convey a variety of information with their calls.

The chilly autumn air on top of the mountain reminds me that it will soon be winter. It is time for the mountain chickadees to leave the socially monogamous partnerships they had while raising their chicks to form larger flocks. Forming social groups is not always simple; young chickadees are joining new flocks, and social dynamics need to be established before the winter storms arrive.

I can hear them working this out vocally. There’s an unusual variety of complex calls, with melodic “gargle calls” at the forefront, coming from individuals announcing their dominance over other flock members.

Examining and decoding bird calls is becoming an increasingly popular field of study, as scientists like me are discovering that many birds – including mountain chickadees – follow systematic rules to share important information, stringing together syllables like words in a sentence.

Songs vs. calls

For social animals, communication is a crucial part of everyday life. Communication can come in the form of visual, chemical, tactile, electrical or vocal signals.

Birds are highly vocal, often relying on vocal communication to effectively interact with their environments and flock members. Temperate songbirds, including cardinals, bluebirds, wrens and blackbirds, have two main categories of vocalizations: songs and calls.

Songs are vocalizations that are used primarily in the spring, during breeding season. Males in temperate regions sing to attract females and defend territories.

Calls are basically any vocalization that is not a song. This category includes a limitless variety of vocalizations that communicate all sorts of essential information.

Most songbird species have complex songs and fairly simple calls. This is why vocalizations sound most melodic during the spring, when birds are attracting mates and breeding.

However, chickadees are unusual in that they sing very simple songs relative to the complexity of their calls. Research suggests this is largely due to their social structure and complex environments. Living in flocks for the majority of the year means they need an elaborate communication system year-round. This is in contrast to many other songbird species that are more solitary during the nonbreeding season.

Scientists know quite a lot about birdsong: It is highly organized and composed of multiple units that are strung together into “phrases,” like how musical notes are strung together in a song.

Some species manipulate their song to sound more impressive, by incorporating new elements or performing impressive acoustic feats through note modification – imagine a trill or an impressive high note.

Some songbirds must learn their songs from their parents and other adult males during a sensitive period in the first several months of their lives. It’s similar to how human children must learn how to speak from adults during a similar early sensitive period.

In contrast, we know relatively little about the structure and organization of complex calls. Scientists have often regarded calls as unexciting and simple compared with birdsong. However, calls are arguably the most important type of vocalization, at least for highly social bird species.

Translating mountain chickadee calls

I spend my days out at our field site in the beautiful Sierra Nevada, following and recording chickadees as they communicate with each other. I have taken numerous focal recordings, where I stand in the forest with a directional microphone, identifying vocalizations and behaviors in real time.

I also have hundreds of hours of recordings taken by automated recording devices called AudioMoths. These allow me to record vocalizations in the absence of people.

The extensive vocal repertoire of mountain chickadees has yet to be fully documented. There are five basic categories of call types:

• Contact calls: communicate identity, sort of like a name, and location.
• “Chick-a-dee” calls: coordinate flock movement and communicate a variety of complex information about the environment, from food availability to predator presence and type.
• Alarm calls: alert others of the presence of a predator.
• Begging calls: used by chicks or females to elicit feeding behavior from males.
• Gargle calls: advertise dominance over other individuals in a flock, primarily used by males.

“Chick-a-dee” calls contain several elements resembling the basic elements of human grammar. Essentially, the various sounds a chickadee utters mean different things, similar to words in human languages. And the way that a chickadee combines these sounds changes the meaning. Word order matters, just like grammar matters in human language. If a chickadee were to phrase its calls in the wrong note order, the call would no longer convey the same meaning, even if composed of the same elements.

The “chick-a-dee” call of the mountain chickadee contains six elements, known as notes or syllables, that can be combined in hundreds of unique combinations to say many different things. These elements are labeled A, A/B, B, C, D and Dh.

Although scientists don’t fully know the meaning of each note in different contexts, it is generally believed that A notes typically contain identifying information about how important the topic seems to the caller, while A/B and B notes tend to further inform the listener of the topic of conversation. C notes contain information about the subject of the call, often a food source, and D notes convey information about the excitement and urgency of the message, including level of threat of a spotted predator or size of a food source. The D notes basically function like exclamation points at the end of a sentence, while the other notes convey more specific information.

Mountain chickadees can use their “chick-a-dee” calls to convey hundreds of different phrases that are relevant to navigating their habitats and social environments. As a hypothetical example, a mountain chickadee call might have the following syntax: A-A-A/B-B-D-D, which could roughly translate to something like, “Listen to me carefully (A-A): there is a predator (A/B) close by (B) and a medium threat level (DD).”

If the note order switched to D-A-B-D-A/B-A, the sentence would look more like: “Noteworthy listen close by noteworthy predator listen to me.” Although all the same elements are there, this sentence is now much more difficult to comprehend. Notes that are out of order can confuse chickadees, preventing them from grasping the correct meaning of the call.

This “translation” is an example based on what we have learned from playback experiments, but the exact meaning will depend on the specific population and surrounding environment.

Analyzing the ‘chick-a-dee’ calls

Back in the lab, I parse through the endless hours of recordings using a deep-learning algorithm that I have modified to identify the specific calls of our chickadee population.

I then use Raven Pro software, developed by the Cornell Lab of Ornithology, to visually inspect and analyze these calls on a spectrogram: a visual representation of sound, with frequency on the vertical axis, and time on the horizontal axis. This visualization allows me to study the structure of calls in great detail.

Studying spectrograms can get me only so far. The next step is to experimentally test different “chick-a-dee” calls out in the wild. Using audio editing software, I manipulate the syntax of calls to either follow grammatical rules or violate them. Then, I broadcast these manipulated recordings out in the forest and observe how our chickadees react to grammatically incorrect calls, which would sound like gibberish to them.

My hope is that this combination of experimental testing of calls and careful visual analysis will provide a step toward understanding the subtle complexities of chickadee communication. I’m trying to home in on the meaning of different syllables and syntax, the grammatical rules.

Back in the forest with my directional microphone, watching the chickadees flit about, I hear different versions of the “chick-a-dee” calls. Some feature more D notes, which would indicate a higher level of excitement. Others feature more A, B or C notes, communicating more specific, identifying information. I am also surrounded by melodic gargle calls, harsh scolding calls and barely audible soft calls.

Next time you find yourself out in the forest, stop and listen to the chickadees as they talk to each other. Maybe you’ll be able to hear the variation in their calls and know that they are talking about different things − and that grammar matters.

Sofia Marie Haley, Ph.D. Student in Cognitive Ecology, University of Nevada, Reno

This article is republished from The Conversation under a Creative Commons license. Read the original article.