Isn't that interesting. Usually these things are maternal, because that's where most of the work happens and it's easy to jam up. But here is something that affects sperm development in a way that doesn't break the sperm completely, just breaks the resulting babies. Must be a complicated pathway.

From my reading of various research etc, metformin has some marginal beneficial effect to blood sugar levels, but it is not clear cut as perhaps you might think. In comparison, what IS undeniably effective is making simple lifestyle changes like going for a walk after a meal, not eating right before bedtime, doing some simple resistance training etc. These have much more measurable effects than metformin, with none of the potential downsides.

That makes sense. Metformin is used as a testosterone lowering drug for feminizing masculine females with PCOS. If it's strong enough to help get rid of a beard on a very hairy woman, it's probably going to do something to a male even though they might otherwise have more testosterone to spare.