Why are there so much teenage mothers in the western world Uk in particular?

Well, girls these days don't know how to keep their legs shut.Why are there so much teenage mothers in the western world Uk in particular?
I have no idea why there are so many teenage mothers in the western world. People say that teenagers are uneducated about sex but how hard can it be to understand that unprotected sex = pregnancy and if the condom splits then that's the same thing. I'm 17 and understand this, I've known this for a long time so I don't understand how others don't, it's not like that's complicated.Why are there so much teenage mothers in the western world Uk in particular?
Many other places reproduce a lot more than the UK. Try China and India for an example.
there r more in th undeveloped world. that is life. nothing wrong about it apart from stuck up peoples opinions