BabyBlue is correct, clomid does not kill sperm, but it can create hostile
cervical mucus...
and the sperm needs fertile
cervical mucus to survive. I just did one cycle of clomid last month, and decided not to take it again for that exact reason. I guess it affects cervical mucus in about 1/3 of users. However, if you do IUIs, it doesn't really matter, since the sperm will then be injected straight into your uterus, and thereby bypassing the cervix (and cervical mucus).