I wasn't analyzing it that deeply. When I took a rubbinic judaism course in University a few years ago (it was either that or calcius), the prof started us off by indicating the documents were written thousands of years ago by scribes who if we showed them how we write today, wouldn't be able to understand it. They spoke differently, and wrote obviously differently. Rather than use the course as a basis of teaching religion, the prof simply indicated it was history. I found it very interesting. The reasons behind why they did certain things was based on their lifestyles back then. They were also the basis for the first laws. He also said to look for the essence of what they were saying versus analyzing each word because a lot of the words had different meaning back then. The bit about having large families I think was for protection. They didn't have governments, or policing organizations like we do now, and to have the strength of a large family was in itself protection. Not to mention the ability to put for a lot of work for the families sustenance.

I think the scriptures are an amazing account of history but in my personal opinion, many organized religions take the words too much to heart, and analyze the information until it no where resembles what it was intended.