Twins

You couldn't have scripted it better - just like a storyline from Eastenders or Hollyoaks, a pair of twins separated at birth managed to find each other in their new lives, fall in love and get married. It's not clear how they figured it out or whether they remained chaste before the nuptials, but then such details are irrelevant to those of us who aren't busy body gossipists anyway.

Considering cases like these, it's easy to see where Islam's insistence on recording and demonstrating hierarchy, parentage and lineage comes from. For those who are unaware, adoption by name is unrecognised in Islam and the status of an adopted child is always apparent in contrast to a birth child; in fact some Muslims hold the opinion that adoption is not allowed at all. I'm not personally aware of what the opinions are on surrogacy or anonymous donorship of eggs or sperm, but the point stands that in all cases knowing your linage is supremely important in Islam.

Of course practise is different in theory and even a strict parental record will allow cases to slip though (due to fraud or administration errors). But seeing how there are now some in the UK who believe that adoption should no longer kept secret perhaps it's the right way to go anyway.