WASHINGTON (AP) – Anatomy at birth may prompt a check in the “male” or “female” box on the birth certificate — but to doctors and scientists, sex and gender aren’t always the same thing.

The Trump administration purportedly is considering defining gender as determined by sex organs at birth, which if adopted could deny certain civil rights protections to an estimated 1.4 million transgender Americans.

But variation in gender identity is a normal part of human diversity, the American Academy of Pediatrics, or AAP, stresses in a new policy that outlines how to provide supportive medical care for transgender youth.

Here are some questions and answers about what can be sometimes blurry lines.

Q: Aren’t sex and gender interchangeable terms?

A: Sex typically refers to anatomy while “gender goes beyond biology,” says Dr. Jason Rafferty, a pediatrician and child psychiatrist at Hasbro Children’s Hospital in Rhode Island, and lead author of the AAP’s transgender policy.

Gender identity is more an inner sense of being male, female or somewhere in between — regardless of physical anatomy, he explained. It may be influenced by genetics and other factors, but it’s more about the brain than the sex organs.

And transgender is a term accepted across science and medical groups to mean people whose gender identity doesn’t match what Rafferty calls their “sex assigned at birth.”

Q: How early can people tell if they’re transgender?

A: It’s normal for children to explore in ways that ignore stereotypes of masculinity and femininity. Rafferty says it’s whether those feelings and actions remain consistent over time that tells. Sometimes that happens at a young age, while for others it may be adolescence or beyond.

Regardless, the pediatricians’ policy calls for “gender-affirmative” care so that children have a safe, nonjudgmental and supportive avenue to explore their gender questions.

Q: What kind of care might they need? A: Transgender people of all ages are more likely to be bullied and stigmatized, which can spur anxiety and depression and put them at increased risk for suicide attempts.

For children, medicine to suppress puberty may be considered, to buy time as the youth grapples with questions of gender identity.

Q: Can’t a genetic test settle if someone’s male or female?

A: “It’s not like we’re going to find a magic transgender gene,” Rafferty says, noting that a mix of genes, chemicals and other factors contribute but is not well understood.

Generally, people are born with two sex chromosomes that determine anatomical sex — XY for males and XX for females. But even here there are exceptions that would confound any either-or political definition.

People who are “intersex” are born with a mix of female and male anatomy, internally and externally. Sometimes they have an unusual chromosome combination, such as men who harbor an extra X or women who physically appear female but carry a Y chromosome. This is different than being transgender.