First, you are miles ahead of most people already, by even giving childbearing any serious forethought. I think it's really important to remember that ALL people have the risk of giving birth to a child with serious disorders. I had to keep this in mind when choosing to have my own children, since my mother was schitzophrenic (although it's nowhere else in my family - but still, by virtue of her diagnosis my kids are much more statistically vulnerable to it). Lots of people with no disorders in their family tree, still give birth to kids with special needs. If everyone stopped having kids out of fear, well, there goes humanity.
The vast majority of people think they wouldn't be able to handle it, and the vast majority of people who end up in that situation, actually handle it very well. There are two ways to look at your situation: the way you are right now (the Worrier way), or the Expert way. Meaning, even if you did have a child with challenges, you will already by an Expert in what they are going through. You'll be way ahead of parents like me who started out clueless.
If you are emotionally stable (as stable as any of us can be given the human condition), mature enough to genuinely put someone else's needs and wants above your own 24/7, and you are kind, then you are fully capable of raising a child - any child. That doesn't mean you personally should, only you can know the answer to that. But it does mean you need to accept that you can't control what kind of child you will have, you can only control how much you want them, and how much you love them.
But you will need to free your mind of worries before you can clearly find your answer.
Best wishes