Mayo Clinic experts say puberty blockers can lead to withering testicles, fertility problems and even cancer among the trans kids who take them, in the latest study to raise alarm about transgender medicine.

The findings cast doubt on the 'reversibility' of puberty blockers — a key claim of the trans activists who promote the drugs, saying they only 'pause' puberty and buy time for trans kids to make decisions about their gender.

Instead, researchers say puberty blockers hurt the development of testicles and sperm production in ways that are not fully reversible and could affect users' ability to have children when they grow up.