Considering that the majority of witches and wizards in the Harry Potter universe are so ignorant of the Muggle world, it's probably safe to assume that they don't spend a great deal of time around muggle people, never mind trying to understand their culture.
So if witches/ wizards are so far removed from the existence of muggles, how is it that there are a significant number1 of muggle/ magical pairings that go on to have families and conceive children?
I would assume that a number of them are from muggle/ muggle-born parents as the witch/ wizard may decide to go back to the muggle life that they experienced as children once their education is finished. But then again it seems that Hogwarts would not prepare magical children with enough skills in which to survive and compete in the muggle world (there was only a single opt-in subject that seemed to deal with anything muggle-related, which was Muggle Studies).
Considering even people like Hermione and Harry who grew up around muggles appeared to entirely live within the wizarding world after school, it seems that even this would be a rare occurrence.
When and where would the wizarding and muggle worlds interact significantly enough that people with such different lives could fall in love with each other (or at least become physically attracted enough to each other to do the do and conceive a child).
1: By "significant number", I mean enough so that an entire ministry department can work full time to mount an inquisition into the blood-status of magical folk who were second generation muggle-descended.