In the above pedigree, the black square indicates the male affected with Hemophilia which is a X-linked recessive trait. What is the probability that the proposed child, which is a male (indicated as ?), will carry the disease?
I started off by trying to figure out the probability that the sister has an X chromosome carrying the disease, which I got as 10/16 (Since the mother must be XcXc or XcX and the father either XY or XcY; possible genotypes are XcX, XcX, XcXc, XcXc, XcX, XX, XcXc, XXc)
I then repeated the procedure for each generation and got the final answer as 9/16. However, the correct answer is 1/8. How do you obtain this? Are my assumptions flawed?