BBC News: Gene for left-handedness is found.
Scientists have discovered the first gene which appears to increase the odds of being left-handed. The Oxford University-led team believe carrying the gene may also slightly raise the risk of developing psychotic mental illness such as schizophrenia. The gene, LRRTM1, appears to play a key role in controlling which parts of the brain take control of specific functions, such as speech and emotion. The study appears in the journal Molecular Psychiatry.
I'm always fascinated with news about handedness. One uncle is ambidextrous, my mother was left handed and made to switch as a child. I was ambidextrous until my teacher objected and made me stop using my left hand. I can still write left-handed, but it looks childish. My teacher ruined me by saying "Your right hand is the hand you write with" well before she got fed up with me writing one side of the book with one hand and one side with the other. It wasn't till I got engaged I knew for sure which way was left. Passengers in my car giving directions learn to say "your side" and "my side" to avoid me having to check which hand the ring is on while I drive.
So left-ness is genetic, not a defect. Not wrong, just different.