It really does depend on where you work, I have worked for some dreadful companies where I wouldn't have risked bringing up the possibility of maternity. I think with the larger companies, they tend to have a more developed policy, certainly one company I worked for had clear work/life balance policies. I would always look at these before taking up a job. As for marriage, I'm still trying to decide on the Phd, but my husband has been my mental sanity whilst doing a degree; it can work, it can be really stressful, but a relationship forces you to maintain perspective.