I'm prepared to believe the Biblical authors are frank. If the Bible were translated completely into modern idiom, some people would consider it unfit to be read to children. All those "begats" and "knew" passages begin to acquire a whole new meaning.
On the other hand, I like the term "begat." It conveys a meaning that no modern word can. I wish the modern transaltions would continue using this term, but unfortunately they don't. Instead you get the very bland phrases like "_____ was the father of _____." "Begat" is just so much more concise and direct.