Then masturbation and contraception are murder - are they not?
Sperm (I assume you are talking about male masturbation here) does not produce a baby until it is combined with an egg.
This is basic level biology here.
Certain types of contraception can be because rather then preventing fertilization they just prevent implantation.
Neither an egg by it's self or sperm by it's self can produce a new mammalian life. Just the way it is.
Take it up with God, Darwin or the flying spaghetti monster if you object but I do not think it will do any good.
Reality remains.