Does marijuana affect sperm/eggs? if so in what way?

Hard to say: Your question asks for answers that are not easily obtained. It is likely it has less effect on sperm, since so many are made,their life is short and the healthiest are more successful. With the eggs,the effect may be significant, as the ones you are born with are all you ever have, Since cannabis use is illegal in most areas, studies of short or longer term use on egg quality is not available