"Puberty blockers and hormone therapy, the two treatments primarily given to minors, are most effective around the ages of 8 to 14, as they can prevent the need for future surgeries in adulthood..."

"... for example, a transgender boy who took puberty blockers might not need a mastectomy later. There are risks to the drug therapies, including slowed bone growth and fertility loss, but evidence suggests that denying the care to adolescents who need it raises the risk of depression and suicide. The push to outlaw such care altogether gained momentum last year as Republicans across the country adopted the issue.... A week before the [Arkansas] law was to go into effect, however, it was temporarily blocked by a federal judge in response to the A.C.L.U.’s legal challenge. The trial is set for July. Transgender adolescents and their families are now living with uncertainty. 'It’s pretty excruciating as a parent to be told by the state that it will become illegal to give your child what she needs to exist,' Jasmine Banks said. Zara added, 'It’s not, like, other people’s decision who I am and what I’m not.'" 

 From "In Arkansas, Trans Teens Await an Uncertain Future/Even as the medical community grapples with how best to provide care to transgender adolescents, some states seek to ban it outright" (NYT).

 

ADDED: Here's a London Times article from 2020: "Giving puberty blocker to ‘trans’ children is a leap into the unknown/A landmark legal review will examine claims that confused young people are being subjected to a giant medical experiment, says Janice Turner." 

An 11-year-old child is probably years from his or her first kiss. Yet the drug they are about to take will almost certainly lead to a medical pathway which will leave them sterile. Since their gametes will never be allowed to mature, doctors will not even be able to harvest their sperm or eggs. Can any 11-year-old understand the gravity of ruling out ever having children? 

Moreover can this child, for whom sex is an unimaginable, probably rather revolting adult business, consent to a treatment which will depress their future libido to the extent they may never have an orgasm? (Imagine trying to explain the concept, let alone the desirability, of an orgasm to an 11-year-old.) These are the ethical issues which make puberty blockers the most controversial of medications.... 

Triptorelin is presented by gender clinics as a “pause button” which need not stop puberty for ever but can give a “breathing space” while a young person decides whether they wished to proceed to transition.... The problem is that almost everyone who takes puberty blockers goes on to transition. Frozen Peter Pan-like, they see classmates develop into adults. Many have already “socially transitioned”, assuming opposite sex names and clothing. Going back is scary, so inevitably they press forward into cross-sex hormones. But would they have transitioned anyway? Most likely not.... 

Doubts about puberty blockers have come from senior clinicians, from LGBT campaigners worried that gender clinics are performing “gay conversion therapy” on future homosexual kids, and from feminists appalled that girls who do not conform to sexist gender stereotypes feel they cannot be girls....