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What the science tells us about sex and gender

Within hours of re-entering the White House on Monday, President Donald Trump signed an executive order asserting that, legally, there are only two genders: male and female. The order strips federal recognition of the gender identity of an estimated 1.6 million trans and nonbinary people, and directly contradicts a number of existing laws and court rulings.

That’s the legal situation, but what about the actual science? Trump’s new definition of sex starts at the moment of conception. But that represents “a dramatic failure to understand biology,” neuroscientist Rachel Levin told STAT’s Megan Molteni. In the moment that a sperm fuses to an egg, we’re all the same, Megan writes — we’re just one big cell.

Read more from Megan for a rundown of the sticky science of sex and gender and how Trump is trying to make gender binary again.

12%

That’s the percentage of trans and nonbinary youth that reported needing to travel out-of-state to receive medical care due to bans on gender-affirming care, per a report published yesterday by the Trevor Project and Movement Advancement Project. Four percent of LGBTQ+ youth moved from one state to another due to related policies or laws according to the report, which used data from the Trevor Project’s 2024 national survey of more than 18,000 young queer people.

People with MS at higher risk of post-pregnancy mental illness

People with multiple sclerosis are significantly more at risk of developing mental illness during pregnancy and in the first year after giving birth than people with other chronic conditions, according to a study published yesterday in Neurology. During pregnancy, people with MS are 26% more likely to have mental health conditions like depression, anxiety, psychosis, or substance abuse than people without MS. In the first year after giving birth, they have 33% higher risk.

Researchers analyzed data from more than 894,800 mothers in Ontario, Canada with MS, epilepsy, inflammatory bowel disease, diabetes, or none of these conditions. Each gave birth between 2000 and 2017. While people with any of these chronic diseases had more mental health diagnoses overall than people without any, those with MS suffered the most.

Why? The study authors pointed to genetic risk of mental illness, risk factors ranging from childhood maltreatment to inflammation and immune dysregulation, the psychosocial stressors of managing chronic disease during pregnancy, and hormonal changes as potential contributors to the increased risk.

Med schools are already overcomplying with rule against affirmative action

Medical schools are being told by their lawyers to stop using strategies to diversify classes that are still legally permitted, despite a Supreme Court ruling against the use of affirmative action in admissions. Experts told STAT’s Usha Lee McFarling that this response to the court decision helped fuel the double-digit decline seen in this year’s overall enrollment of Black, Hispanic, and Indigenous students — and may be a form of discrimination in itself.

“This was entirely predictable and may just be the beginning of steeper declines,” James Hildreth, president of the historically Black Meharry Medical College, told Usha. “This represents a huge setback. This is not a time for us to reverse course, or lose highly qualified candidates.”

Read more from Usha on what exactly is happening at medical schools.

Why are some people still taking baby aspirin?

The standard guidance used to be that almost anybody could take a daily, low-dose (“baby”) aspirin with little risk, in order to prevent heart attack or stroke. But in 2019, the American College of Cardiology and American Heart Association narrowed those recommendations, so that only those who are at elevated risk for atherosclerotic cardiovascular disease, who are also under 70 and without bleeding risks, should take a daily baby aspirin.

But that message might not have reached everyone, according to a study published yesterday in JAMA. Using national survey data from more than 18,000 people between 2011 and 2023, researchers found that the percentage of white people taking daily baby aspirin against recommendations fell by 8.3%, compared to 0.2% among Black patients. The researchers noted that further attention to reducing unnecessary aspirin use is “warranted,” but did not propose any specific strategies.

The duty of clinicians if ICE enters the hospital

This week, the Trump administration revoked longstanding protections that barred Immigration and Customs Enforcement (ICE) officers from conducting raids in “sensitive” areas including hospitals and medical clinics. In a new First Opinion essay, clinician and anthropologist Eric Reinhart argues that this decision is not just cruel, “it is a public health catastrophe in the making.”

Health care workers must be prepared to protect their patients and uphold their own ethical obligations, Reinhart writes. This involves developing clear protocols for responding to ICE. Read more on how Reinhart believes health care workers should respond to the change.

What we’re reading

• What a $20,000 longevity clinic really buys you, New York Times

• Trump administration’s abrupt cancellation of scientific meetings prompts confusion, concern, STAT

• Long Covid patients are frustrated that federal research hasn’t found new treatments, KFF Health News

• RFK Jr. invested in gene-editing biotech, is owed millions for book advances, disclosures show, STAT
• FDA allows standalone use of nasal spray antidepressant Spravato (esketamine), NPR
• RFK Jr. to face key Senate committee hearings next week, STAT