This transgender girl and her nonbinary friend are doing their homework. Such teens can feel that once puberty starts, their body doesn’t match their gender. But with gender-affirming health care, they can develop an adult body that does fit. Lisa5201/E+/Getty Images Plus
The main hormones that guide puberty are estrogen and testosterone. Both have many jobs and act as chemical messengers to carry out those tasks. Estrogen plays a role in keeping the bones, brain, heart and liver healthy. Testosterone also helps keep bones and muscles healthy. It also affects mood and energy levels.
During puberty, these hormones take on additional roles. They tell the body to start producing what are called secondary sex characteristics. Those include a beard or breasts.
Transgender females may take estradiol, the most potent of the estrogens. The molecule is identical to that produced in the bodies of cisgender females. Evgeny Gromov/iStock/Getty Images Plus
People designated female at birth typically produce more estrogen; those designated male at birth usually make more testosterone. But anyone with testes or ovaries makes both hormones, notes Douglas Austin. How much of each they make will vary over their lifetimes.
Austin is an endocrinologist at the Fertility Center in Eugene, Ore. One aspect of his work is to manage those hormones that determine how our bodies develop. He works with transgender kids and their families. He helps adjust hormone levels in these kids during puberty to guide their bodies’ development.
For many of these young people, puberty blockers are the first step, says Austin. If given soon after puberty starts, these blockers act like a pause button. (This medication also may be given to cisgender kids who begin puberty too early, he says.)
This is a model of a testosterone molecule. Transgender males may take this hormone during puberty to develop male secondary sex traits. Evgeny Gromov/iStock/Getty Images Plus
When puberty starts, a part of the brain called the hypothalamus sends a message to its neighbor, the pituitary gland. It instructs the bean-sized gland to message the body’s testes or ovaries. Spit out more hormones — testosterone or estrogen — it says. Blockers get in the way of this, says Austin. They stop puberty’s call to produce more such hormones. That also stops the development of body changes such as breasts or facial hair.
Mary knew she was transgender from a young age, about 3 or 4 years old. But some transgender people don’t realize it until later, often around puberty. That’s one reason blockers can be so helpful. They give teens more time to explore their identity before their bodies undergo permanent changes. Mary’s doctor prescribed a blocker called Lupron. This stopped her body from making extra testosterone.
‘Bio-identical’ hormone therapy