OK, noboday likes to think of their parents "doing it", but, inspired by the Birthday no, 1 thread, it occured to me that the number one song nine months before you were born might be a little more informative, and in some cases may explain a thing or two.
Be warned though, if you look this up, you may never be able to listen to a certain classic song with a straight face again - especially with your mum or dad in the room!
Go here, click on the Birthday Number One button at the top, and enter a date 9 months before you were born...
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For me, Jumping Jack Flash by The Rolling Stones - says it all really!!