[emilfihlman]

I believe quite contrary to the other responses you have received, it's not about kindness really, but mostly a function of where it would affect people the most and how those companies operate and are formed: through a very small circle of friends who know each other and because such companies are in minority such discrimination would be quite invisible whereas Big Corps(tm) can just eat such costs quite easily and they are held to the standard of hiring more. Smaller companies (that require higher education or good thinking skills) also probably get people who care about their career more at that point, getting kids at a young age is pretty low education thing to do (just as a statistics on who gets kids and when) and those people work in very gender separated fields usually.