If you love something, set it free
If it comes back, it was, and always will be yours.
If it never returns, it was never yours to begin with.
If it just sits in your living room,
messes up your stuff,
eats your food,
uses your telephone,
takes your money,
and never behaves as if you actually set it free in the first place, you either married it or gave birth to it.
English Law prohibits a man from marrying his mother-in-law. This is our idea of useless legislation.
~Author Unknown
Albert Einstein and Charles Darwin both married their first cousins (Elsa Löwenthal and Emma Wedgewood, respectively).