> it seems to be doing something to the sperm, and not causing genetic changes. To be clear, spermatogenesis takes roughly 75-120 days, so this is consistent w

> it seems to be doing something to the sperm, and not causing genetic changes. To be clear, spermatogenesis takes roughly 75-120 days, so this is consistent with metformin causing genetic changes to the sperm when or after they are formed, with those genetic changes being propagated through the germ line to children conceived by the sperm. But it's true that the (very preliminary) data does not suggest that this is causing permanent genetic changes in the father.