[This is an entry to the Adversarial Collaboration Contest by flame7926 and a_reader.]

[Content note: suicide, depression, transphobia, self-harm]

Transgender childhood transition is a hotly debated topic, with extensive media coverage devoted to it in recent years. (pro: BBC, The Lancet and The New York Times ; contra: The Cut, New Statesman and The Globe and Mail).We see plenty of stories of transgender children (or gender dysphoric children and gender nonconforming children), both in the media and in the blogosphere. As early as 2 or 3, defying the expectations of their family, those children show a persistent and insistent preference for many things associated with the other sex: little boys want long hair and love dresses, Barbie dolls, Disney princesses and mermaids; little girls, instead, dislike stereotypically feminine activities and prefer rough and tumble play, refuse to wear dresses and insist to have their hair shorter and shorter.

Sometimes, from the very beginning, the toddler corrects the parents: "I'm a boy /girl!", but more frequently cross-gender behavior is more prevalent. This is only sometimes followed with the child expressing preferences that would be termed gender dysphoria. The child (born and currently living as a as one sex) says to their parents something like "God made a mistake" or "something went wrong in Mommy's tummy" because he should have been a girl, not a boy (or the other way around). The worried parents search information on the internet and seek out the advice of an expert. There, they usually find one or both of these contradicting opinions:

Gender-affirming approach

Listen to your child – he/she knows best his/her gender. Let your child be his/her true self. It's your responsibility as a parent to support your child in all stages of his/her transition: social transition now, puberty blockers at the beginning of puberty, cross-sex hormones in adolescence, surgery at 18. To oppose it is child abuse. Transphobia costs lives: 41% of transgenders attempt suicide. Do you prefer a happy daughter or a dead son?

Or:

Therapeutic approach

Your child is just confused. He/she is too young to understand gender and to take such important decision. 80% of gender nonconforming children desist. You, as a parent, have the responsibility to correct his/her wrong behavior. If you tolerate it, gender dysphoria will be reinforced by repetition and persist to adulthood. To encourage your child's delusion is child abuse. Transgenders individuals face lifelong struggle and often suffer from poor mental health: 41% of transgenders attempt suicide. Do you really want that for your son, when he could instead come to accept the body he was born with?

The first approach is promoted by transgender activists, the second by the conservative media, but both are supported by some experts. The "Gender-affirming approach" is supported by the Dutch team from the Gender Clinic at VU Medical Centre, Amsterdam, who elaborated the typical transition treatment for minors, with puberty blockers at 12 and cross-sex hormones at 16, and, in the US, by Kristina Olson and others from the TransYouth Project. The "Therapeutic approach" is supported by Kenneth Zucker and his team from the Gender Identity Service at Centre for Addiction and Mental Health, Toronto, and, in the US, by Paul McHugh at Johns Hopkins University School of Medicine. There are also experts such as Debra Soh, once a gender nonconforming girl herself, that advise parents to wait and see until adolescence, because in many cases gender dysphoria desists spontaneously, without intervention.

Who to believe when the experts disagree? Let's see the evidence.