What do you think the reason is?

This morning in my way to work, I saw a girl post a belly picture on my Facebook. Her and the guy have been together. A few years, but it go me thinking... 40, 30, even 20 years ago, unwed people having babies weren't remotely as common as they are now. "Unwanted" pregnancies, and in turn abortion, weren't remotely as common as they are now. And now, birth control is much more readily available than it was back then (in my state at least, if you don't have health insurance, and you make under I believe 36k a year, you can apply for free birth control, I did it for several years before I got married and got health insurance).