Hmm this is so true (but not for all teen mums).
My cousin is 20 and expecting her 2nd baby, she had her 1st at 17, her sister had her 1st at 16, the mother had her 1st at 18, the gran had her 1st at 17 (sensing a pattern).
oh and just to add to confusion the only one im truly related to is my preg cousin as she is my uncles kid the rest are non blood related to me (but they still like family).