Hernia question....

Dh had a hernia when he was little and had surgery when he was in kidnergarten. What are ds's chances of having one as well? What causes hernias?

If it matters, the scar is above and to the left of his penis, as you look at it, sort of along the fold of leg/hip/stomach area.

Thank goodness dh never reads here, he'd be mortified to know that I was talking about his 'nether-regions.'