Vegeta did say so himself during the Saiyan arc that he's not interested in conceiving powerful hybrids due to the consequences it can bring and he pretty much implied he's a virgin to Bulma after the Frieza arc. It's one of the reasons why I love the idea behind the Saiyans being a warrior race and how it relates to Goku's character. Saiyans don't care for sex like humans would (Since they only see it as a way to produce, and nothing desirable) and thus are more capable of acting rationally when it comes to it. Hence why Vegeta never had his way with woman even when he could and didn't allow any form of desire to cloud his thinking when it came to producing hybrids.