Why all of the teenage pregnancies?

Why are so many teen girls planning to get pregnant nowadays? Do you think it has anything to do with the shows like mtv's "sixteen and pregnant" and stuff like "the secret life of the american teenager"? I ask this because I see everyday girls of like 16-18 that plan to get pregnant,and why would they do that? Is it the new "in" thing? I hope these girls realize that it's a lot harder than carrying a puppy in a purse,and chances are,they won't be with the guy for the rest of their lives. It does happen sometimes,but it's a rarity anymore. Anyways,my question,why are girls so so so young planning pregnancies anymore? Does this bother anyone else,when they think of the lives these babies might have (getting tossed from babysitter to babysitter so the parents can finish high school even,getting more care from people that aren't the parents because of how busy the parents are with school,wouldn't it make mores sense to wait until you've graduated college or were at least in college before you plan a baby? How can one be financially well off enough (unless they have a rich family) before they're done with school to plan a baby? I can understand if an accidental pregnancy happens,but planning one before even done with high school? Someone help me understand this,because it confuses me. I realize these girls may be great moms,but shouldn't they be waiting until they and not taxpayers or family members can support their children?