[glaugh]

Yeah. A lot of the warnings on the side of the box are based on really suspect data from a very long time ago (Abraham Morgentaler at Harvard is my go-to for this) but the point cj raises is legit.

When a man takes exogenous testosterone, their endogenous production (in the testicles) plummets. This is largely fine, but the production in the testicles also leads to sperm production, and that gets lost.

The solution to this is HCG, which stimulates some testicular production. But it is not a perfect solution, and recently CA has made it much harder to use HCG for this purpose (which was always off-label).