Too much detail...

OK, I know no one will be interested in this but me. Considering this is my blog, you're just gonna have to suck it up. Read it or skip it. Feel free to let me know if my stats are messed up. Inquiring minds want to know.
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Cystinuira odds:

OK, I’m told that cystinuria occurs in 1 in 10,000 people. If we assume that the disease inheritance is by simple mendeleevian genetics for a recessive trait (which I believe is nearly correct), we get this:

Randomly selected Person:
Odds a parent has the gene: 1 in 50
Odds a parent with the gene passes it to a given child: 1 in 2
Therefore,
Odds a a parent has the gene and passes it on: 1/50 x ½ = 1 in 100
And finally,
Odds that both parents have the gene and pass it on: 1/100 x 1/100 = 1 in 10,000.

Our children:
Odds TW or I have the gene: 1 in 1
Odds the wife or I pass the gene on to a given child: 1 in 2
Therefore,
Odds the wife or I has the gene and passes it on: 1/1 x ½ = 1 in 2
And finally,
Odds that both parents have the gene and pass it on: ½ x ½ = 1 in 4

Our family:
Odds TW’s sister or one of my brothers have the gene: 1 in 2
(given that they don’t have the disease, trust me on this)
Odds they pass it on: ½ x ½ = 1 in 4
Odds one of their spouses has the gene: 1 in 50
Odds they pass it on: 1/50 x ½ = 1 in 100
Odds that both have the gene and pass it on: 1 in 400


Hypothetical situation where one of my brothers gets TW’s sister pregnant:
Odds TW’s sister or one of my brothers have the gene: 1 in 2
(given that they don’t have the disease, trust me on this)
Odds one of them passes it on: ½ x ½ = 1 in 4
Odds both of them pass it on: ¼ x ¼ = 1 in 16.
Therefore, I recommend against my brothers getting my sister-in-law pregnant.