Hi multimedia9 - welcome to INForum!
When you do a Google search for "Law of Sex" it usually is used as part of a longer phrase - e.g. "Law of Sex Discrimination", "Law of Sex Crimes", "Law of Sex Offences" -
It is rarely used as a term on its own, and so it is unlikely that someone will want to pay a premium for it. It would work alright as an adult site, perhaps the name of an adult movie.
I'd say it's worth mid-$xx on a wholesale basis.