Two in a Million

So, I've watched a few episodes of the above show. (TLC show, pretty good!)

The families had children with very rare conditions, say 1 in 40,000 chances. What shocked me, was that some of these children were middle kids. As in, the parents had a child with a disability (ex: a painful condition called Schwartz Jampel Syndrome) and then chanced it, and had another child.

My question is-- if you had a child with a rare, painful condition, would you still try for another kid knowing that there is a chance that the next child could share the same disability?