Pretty is what we can fantasize about - imagining having known about my brca1 before cancer struck

I'm reading Jessica Queller's Pretty Is What Changes, chronicling how she discovered that she was brca1 positive and the medical decisions she made therewith. 
The bad: tediously name-droppy. 
The good: Queller really lets us in on what it feels like to consider cutting off a part of your body because it might save your life. And probably save you from a serious and grizzly illness. And whether or not that is too much of a decision for us all.
I find it strangely comforting to read about someone who had a prophylactic double mastectomy in response to learning about her cancer gene. It isn't that I want to share the misery – I really really desperately don't – but that I can fantasize that avoiding cancer is possible. Dramatic, traumatic, but possible.
This is a genetic disease. This means I was born with the code that would lead to this, sort of. So, it feels silly to me to think of changing who I was born to be, – “Oh, what if I didn't have this gene?” – but perfectly reasonable to dream about going back in time, learn that I had the gene, make the stunningly proactive decision to have a drastically body-altering surgery, and screw around with my hormones by removing my ovaries….
Oh, wait. I guess that wouldn't have been me, either. Not the type for extreme prevention, given my lifestyle habits.
Specifically, I kind of lived on peanut M&Ms for a while, and yes, I have a bad habit of staying up into the wee hours of the new day, and exercise is a dirty word. I think these things may not have helped, but with the gene statistics being what they are, my behavior probably had almost nothing, if anything, to do with my cancer.
But where I feel simmering though irrational guilt, and really want to reach out toward the hope of cancer evasion, is in the possibility of my having passed this code along to my children. It's a cruel coin toss.
What will my children choose? Will they get tested? Will they have children? Will my daughter, if she tests positive, go the radical mastectomy and oophorectomy route?
Maybe by then that won't even be necessary. Maybe a little vaccination spray up the nose gives them a cold that cures the cancer.

(Or maybe it turns them into brain-eating zombies.... )