The Economist had an interesting article about "the rich getting richer" (at least in incomes; not net worth) theme recently.
It turns out, most of if is driven by the rise of dual-income couples.
50 years ago, most households had a single earner. Whether you were a doctor or a line cook, the wife would most likely stay home. And for those couples where a woman did work part time, it was in lower earning households, so this would pull up the lower income household closer to the middle.
These days people are generally marrying people with similar career interests. So doctors are marrying doctors, lawyers are marrying lawyers, and waiters are marrying waitresses. So when you have dual-earning couples with $100K+ salaries, it really impacts the household income statistics in an unprecedented way. No one earned money like this two generations ago.
So I guess if you want to blame anyone for rising inequality, you can blame the feminists ;-)