"If you have kids they will suffer because of their genes. So don't."
Firstly, everyone has to suffer through life, including your kids. There isn't some scenario where a person will never encounter suffering in their lifetime. It's just not a real thing. Sure, you can look at someone's life on a surface level and say "they don't have suffering" but it's not accurate. They could very well have gone through suffering to get wherever they are. Or they could still be suffering, you don't know.
Perhaps your meant that they're suffering more than others.
This reminds me of people saying you shouldn't have kids if you're on the Autistic Spectrum, because it would increase the chances of having an Autistic kid. Well, for people on the Spectrum, this is a non issue. Why? Because you don't suffer from Autism, any suffering is entirely because of other people. This is objectively factual because some people will cause you suffering while others won't. If no one were treated poorly because of baldness, would anyone have an issue with being bald? No, of course not.
Suffering can't even be avoided in the best of circumstances. You can have the best genes in the world and still have children with cancer, leukemia, premature etc. The list goes on. Having good genes doesn't shield you from that.