For parents of transgender children, a complex question is emerging: How early is too early for medical transition to begin?

As the debate continues over which bathroom transgender people should use, families and doctors are rewriting the rules as they decide when and how to start medical intervention, with some deciding to start before transgender youth hit puberty.

About 1.7 percent of American youth identify as transgender, and that estimate is conservative since the population is likely underreporting.

“I feel comfortable saying that any survey of LGBT identity likely underestimates the full population because it only accounts for one part of sexual and gender minority status, ‘identity’,” said Bianca Wilson of the Williams Institute, a national think tank at the UCLA School of Law that advances sexual orientation and gender identity law.

In addition to fighting for acceptance, transgender children and their families are faced with medical questions that could be life-changing. These decisions are even harder for those young trans and gender nonconforming people who don’t have family support. Estimates show that about 40 percent of homeless youth identify as LGBT.