They could but why bother? What does an OEM gain by bundling say Firefox instead of IE? It's easier for the OEMs to maintain the status quo.

Please don't tell me you're that naive. While strictly in terms of health teen pregnancy may be fine but you have to consider the social aspects. The mother will probably drop out of school so there goes any chance of a decent job. It's a very stressful thing, especially when the fathers tend to leave, for someone so young and the upbringing of the child will undoubtedly suffer. Increase rate of suicide compared to other teenagers. There's a bunch of other problems too. Just type teenage pregnancy into google.