The second part of the NPR story is now available. Of particular interest is the new and more controversial treatment of older children, that is, the use of hormone blockers to delay puberty. From the NPR story:
To put off puberty, children –- usually between 10 and 13 — are injected with hormone blockers once a month. Spack explains that the blockers only affect the gonads, the organs responsible for turning boys into men and girls into women. “If you can block the gonads, that is the ovary [in women] or the testis [in men], from making its sex steroids, that being estrogen or testosterone, then you can literally prevent … almost all the physical differences between the genders,” Spack explains.
Practically speaking, what is the result?
Without testosterone, boys will not grow facial or body hair. Their voices will not deepen. There will be no Adams apple, and height growth will slow. Without estrogen, girls will not develop breasts, fat at the hip, or menstrual periods. And since most growth happens before puberty, if you block estrogen — and therefore puberty — girls will grow taller, closer to a typical male height.
Then the older child (who is now a teen) can make a decision about whether to pursue development of the preferred gender identity:
The hormone blockers are the first stage of the treatment, but there’s a second stage that’s possible. Once children have postponed puberty for three or four years, at around age 16 they can choose to begin maturing sexually into the opposite gender, the gender they want to become. To do this, they begin taking the hormones of the opposite sex. For males, taking estrogen at this point will bring on breast and hip growth — and all the attributes physical and emotional of females. The reverse will happen for girls who take testosterone. Spack says this treatment can help make an adult transgender male almost indistinguishable from a biological male in terms of physical appearance.
This does not, of course, change their biological sex, but it does affect their gender identity and is intended to help resolve distress associated with gender dysphoria. The article indicates that the side effect is sterility.
As for studies cited, the NPR report mentions to groups that have been intervening with older children in different ways:
The Portman clinic has treated 124 kids since 1989. It requires children to live as the gender they were born with. And 80 percent of its patients — once grown — chose as adults to keep their biological gender.
The opposite outcome was seen by the researchers in the Netherlands who first developed the hormone-blocking treatment. They have treated 100 patients and all chose — as adults — to live as the opposite sex.