The transgender issue is complex and controversial. For an overview of the main issues, it’s hard to beat an article published this week in Medscape Medical News written by Lisa Nainggolan (free registration required). She covers most of the headline topics without exaggeration or taking sides and includes links to some of the most important recent research. Here are some excerpts:

The number of transgender children is growing rapidly. Psychiatrist Annelou de Vries, the head of The Dutch Clinic, now receives 600 referrals a year for gender dysphoria. A UK clinic found that its referrals had increased 50-fold over 12 years for reasons that “are not fully explicable.” And there has been a sudden switch in the ratio of sexes. Natal females outnumber natal males three to one, especially in children over 11.

A further complication is that there appears to be a rapidly growing sub-group of persons, mostly natal females without a history of gender dysphoria who ask to transition in their mid-teens. Those with “rapid-onset gender dysphoria” (ROGD) also appear to have mental health issues.

“There are many factors that people need to look at, whether it's co-occurring autism-spectrum disorder or some general psychosocial vulnerability where these kids feel that they just don't fit in and they are looking for a place to find themselves,” says Dr Kenneth Zucker, a Canadian expert. “Or if they have pervasive mental health problems that are making them feel bad about themselves and they are looking for a way to feel better.” However, other doctors deny that ROGD exists.

Be careful. A number of doctors are questioning the need for irreversible treatment. “The evidence of medium-term benefit from hormonal treatment and puberty blockers is based on weak follow-up studies,” one group said in a letter to The Lancet last year. And guidelines do “not consider longer term effects, including the difficult issue of de-transition.”

Another letter in Archives of Disease in Childhood asserted that: “To halt the natural process of puberty is an intervention of momentous proportions with lifelong medical, psychological, and emotional implications. We contend that this practice should be curtailed until we are able to apply the same scientific rigor that is demanded of other medical interventions.”

“The health consequences of gender affirmative therapy [for youth] are not trivial and include potential sterility, sexual dysfunction, thromboembolic and cardiovascular disease, and malignancy,” wrote Dr Michael Laidlaw in a letter to the Journal of Clinical Endocrinology & Metabolism. Especially when “the stated quality of evidence…is low…how can a child, adolescent, or even parent provide genuine consent to such a treatment?”

Can mental distress be alleviated by puberty blockers? According to the spokesperson on transgender issues for the Endocrine Society (US), “The medical consensus is that harms from short-term puberty blockade and from hormone therapy…seem to be modest, while the harms from failure to treat transgender people are great.”

But Nainggolan points out that this assertion is based largely on anecdotal evidence and that research to prove this is scanty. “There is some published evidence in support of the gender-affirming approach, albeit very short-term because puberty-blocking therapy was only broadly initiated for this purpose within the past decade,” she writes.

Suicide amongst transgender adults. A 2011 study in PLOS One found that the mortality rate was double amongst 324 Swedish adults who had used cross-sex hormones followed by gender reassignment surgery between 1973 and 2003. And the suicide rate was nearly 20-fold higher. de Vries says that a Dutch study reached similar conclusions, but she attributes these dismal statistics to poor mental health reinforced by stigma and discrimination. She believes that the earlier people receive treatment, the better their chance of beating the odds.

The “de-transitioning” controversy. An unknown number of people regret their decision to undergo sex-reassignment surgery. But there seems to be very little appetite for researching this issue. James Caspian, a British psychotherapist, tried to initiate a research project at Bath University. But the university banned it because the transgender community would have vilified it on social media. “This is a conversation that is being suppressed — this is a conversation that needs to be had,” he told Medscape Medical News.

Are puberty blockers healthy? Hormone treatment normally causes infertility. Transgender advocates respond that most of the children they treat say that they don’t want to have biological children and that in any case they can adopt a baby when the time comes. “When you have someone who is stunted at an early age of genital growth, you are not going to have normal adult sexual function. Can you really make a choice about that at that age?” asks Dr Laidlaw.

Why not wait? Critics of puberty blockers argue that the best policy is “watchful waiting”. Psychological therapy can “alleviate gender dysphoria in children, thus avoiding the radical changes and health risks of gender affirming therapy,” says Dr Laidlaw. “This is an obvious and preferred therapy, as it does the least harm with the most benefit.” But supporters say that this approach does not alleviate the distress gender dysphoric children feel; they need immediate treatment.

Michael Cook is editor of MercatorNet.