Generation 1 2 3 4 6 5 6 7 SolutionThe chances of their firs

Solution

The chances of their first child showing the trait is 50%

As this trait is being carried by the females in generation II, and in generation III due to the congenial marriage among the family members the homozygosity of trait increases.

Due to which this trait again shows up again generation IV. If the individual IV-4 and IV-7 get married, which is again congenial marriage among the family member. The risk factor for the children having this trait increases.