A Question Of Selfishness

I'm going to write about something that isn't going to be very popular but has haunted me from the moment the migraines started almost a decade ago. I had fifteen good years of fertility in front of me, so I had been able to push it aside most of the time.  If you do your math, you'll see that there's really nowhere for me to push it to anymore. Even after all this time, it's a question I still don't know how to answer. There is no judgement in it, as I really don't know where I stand.  It's just a question that goes round and round my head as more and more baby bumps seem to cross my path and cover the magazines at the checkout counter.
Is it selfish to be sick and have a child, knowing full well you could pass your illness to them?
Eye color, hair color and a risk of breast cancer.
A crooked smile, funny laugh and depression.
Height, weight and an autoimmune disease.
Part of me thinks that life is hard enough, who wants to risk adding further hardship to the person they will love the most in this world in order to silence the desire that every atom of their being is screaming out for?
The other part of me can't think over the screaming.  It's deafening and somehow more painful than anything I've experienced before.  As I think I mentioned, in over a decade of physical pain, I've sadly lost connection with my body and with it any intuitiveness I once possessed. But this desire is so intense, even in my most disconnectedness, I can feel it as acutely as any physical pain I've ever had.  So I try to rationalize it out, causing a whole new line of questioning.
Every child is at risk of some hereditary misfortune, so is an increase of 10% of that risk worth crushing my dreams?  This one is easy to answer with the cynical reply of you could breathe the wrong air on the wrong day and your risk could increase that much. But then the next questions come and what seems impossible happens; I lose my cynicism. I ask where I should make the cutoff, at 25%, 50% 75%?  And who should I trust since those percentages vary depending on who I talk to and what I read?  Should I believe that I can somehow decrease the risk by doing certain things such as eating a very strict diet that only Gwyneth Paltrow could follow?  Is that strict diet, exercise and meditation regime just an attempt to control the uncontrollable?
Which leads my spinning mind to the realization that "increased risk" is just one way of trying to claim some mastery over that which can not really be mastered.  After all, doesn't everyone's chances just come down to 50/50? Either you pass your illness on, or you don't.
So for a moment I think I've found an answer.  Then my mind spins some more and I realize that it's not as simple as trusting fate.  For instance, if someone warned you that if you cross that bridge there is a 75% chance something horrible will happen, you wouldn't cross it, would you?
Of course you wouldn't. And neither would I. So that just leads me to my final question:  What do you do if you need to get to the other side?