I was diagnosed with very low T (below 250)several years ago and Testosterone therapy made a HUGE improvement in my quality of life. My concern is, if for some reason I had to stop taking Testosterone (i.e., a cancer diagnosis, or inability to afford it if I lost my insurance coverage) would I become impotent? I assume that since my T level was originally low, and since beginning treatment my testes have not had to work, they may no longer be able to produce any T at all. My natural level right now may possibly be zero. (I make the distinction here between infertility and impotence – at my age I am no longer interested in having children, but I AM worried about the prospect of becoming sexually non-functional).