The bad thing about having a lethal, besides having a baby and then having to put it down, is losing all that time and money on the mare being bred and then losing all that.
I think it's wise, Lynn, that you're having him tested, you need to know for your own mares. However, it kinda works both ways. If you know about your stud, super. If you/they know about their mare, super. Only one party has to be negative, and then you don't have to worry about it... but surely a safer bet all the way around.
When I pulled up that OLWS stuff, it did say that some "tobianos" have the gene... I'm assuming the ones that have overos in there somewhere on their papers...hadn't ever heard that before until I read that.
Course if the stud is negative, breed away....HA!