Research shows that transgender youth whose families affirm their gender identity have a 52 percent decrease in suicidal thoughts, a 48 percent decrease in suicide attempts and significant increases in self-esteem and general health.
Since a someone (I’d rather not disclose the relationship, autistic FTM) I know started suffering from gender dysphoria I’ve read all the peer-reviewed papers on the subject I can find and this is not well established. There are no medical trials to support this either way.
If I’m right, it’s a single piece of research to support these figures looked at vulnerable youths e.g. something like homeless or a drug problem. It’s questionable how broadly these numbers apply to the full population.