Not always. I don't deal with it any more, but when I worked at a small company, I saw the health insurance costs per employee. The monthly costs on a younger single woman was significantly higher than on a single man, I suppose due to the possibility of pregnancy.
Anyway, I don't have a huge problem with the reversal of roles on a temporary basis. When I was a kid, my dad was out of work for a while. He worked at a local factory and the head of the union local was a hothead (not just on union stuff either - I was friends with his sons). Like clockwork, every 3 or 4 years, they were out on strike - sometimes long strikes. (We even ended up on food stamps because of one of the strikes.)
Eventually, the company packed up and moved overseas. A lot of good all those strikes did...
This was at the end of the Carter years and coming across a new job was not so easy for someone his age with basically no skills. My mom already worked part time, so she switched to full time for a while until things got better and my dad stayed home. Once my dad got another decent job (about 2 years later), she went back to part time and eventually stopped working.