Antonio Guillamón Fernández

The inclusion of transgender women in women's sports categories is a controversial decision. To compare body composition and physical fitness between transgender and cisgender women, a team from Brazil has conducted a meta-analysis encompassing 52 studies and 6,485 individuals, analysing these values before and after gender-affirming hormone therapy. Although trans women showed greater lean mass—an indicator of muscle mass—there were no significant differences in upper or lower body strength, nor in maximum oxygen consumption, compared to cis women one to three years after hormone therapy. ‘The current evidence is, for the most part, of low certainty and heterogeneous quality, but it does not support theories about the inherent athletic advantages of trans women over cis women,’ say the authors of the study, published in the British Journal of Sports Medicine.

Adolescent boys respond aggressively when they perceive that their masculinity is threatened, an analysis shows. In the study, aggression was higher when boys' motivation to follow what is considered 'typical' for their sex came from external expectations - for example, when their parents believed that men should have more power - rather than their own expectations. The study, which analysed data from 207 boys aged 10-14 and one of their parents, is published in Developmental Science.

A study published in JAMA Pediatrics has analysed bone density in 75 transgender youth who underwent hormone blockade in adolescence, followed by hormone treatment.

An analysis of data published in the journal General Psychiatry with more than 66,000 diagnoses of gender dysphoria, mostly made in the United States, concludes that prevalence increased between 2017 and 2021, and that the median age decreased over the same period from 31 to 26 years.

The International Athletics Federation has decided to ban transgender athletes who have transitioned after puberty from participating in international women's competitions. Although there are currently no trans athletes competing on the international circuit, the Federation "decided to prioritise the fairness and integrity of women's competition before inclusion", according to the statement issued. At a press conference, its president, Sebastian Coe, said: "We will be guided by the science that will inevitably develop in the coming years around physical performance and male advantage. As more evidence becomes available, we will review our position.

A journalistic investigation by BMJ reporter Jennifer Block finds that more and more children and adolescents identify as transgender and are offered medical treatment, in particular in the United States. The reporter analyses scientific evidence showing this increase in the number of treatments, as well as the guidelines of US medical bodies. She also interviews experts from different countries, laying out the controversy among professionals about the scientific evidence used to make decisions about the initiation of treatment.   

A study published in NEJM that followed a cohort of more than 300 transgender and non-binary youth, aged 12-20, for two years concluded that hormone therapy led to improvements in their symptoms of depression and anxiety.