Regarding the possible birth defects - there will be none while you are cycling steroids. There could be indeed birth defects if your wife were using steroids while she is pregnant, but your semen will be just the same. Regarding the possibility of conceiving a child while on cycle - well, there is a misconception that it is impossible to conceive a child while on cycle, but it is well possible - just the probabilities are slimmer. However, I personally know two guys who got their wives pregnant while on cycle, so I have personally seen that happen.