testis

Instead, a subtle form of natural selection within the testes appears to give certain mutations a reproductive advantage, allowing them to become more common during sperm formation.

If a human embryo has XY chromosomes the SRY gene leads to the formation of testes, which then produce hormones including testosterone that lead to male development - and can increase muscle mass and strength.

The masculinity crisis seizing our land saw surprising numbers of Gen Z men break conservative to vote Trump back to office and, before that, a push for testes tanning.

In the brain, sexual differentiation starts before birth and results from a combination of sex chromosomes in brain tissue, sex hormones produced by the testes or ovaries and the environment.

Previous research has shown that STK33 is enriched in the testis and is specifically required for the formation of functional sperm.