On the other hand....for wannabee southpaws:

Can an Ultra-Sound Test Make You Left-Handed?
STOCKHOLM, Sweden (Reuters) - A Swedish study of 180,000 young men showed routine ultra-sound
examinations of the fetus can affect the brain and lead to left-handedness, Swedish radio is reporting.
The study by Uppsala University Hospital and the Karolinska Institute showed that men born in the 1970s
who had been exposed to ultra-sound tests while in the womb were more likely to become left-handed.
Most people are predisposed to become right-handed with only about six percent becoming left-handed.

If you can't see the bright side, polish the dull side.