Three families each have three sons and no daughters. Assuming boy and girl babies are equally likely, what is the probability of this event?

Three families with three children all boys

parents-2

children-3

total-5 times 3 = 15

then boys-3 times three=9

Answer: 9/12

Percentage:75%

I don't think it matters how many families are involved.

You're talking nine live births, and the probability of a

male birth each time is 50%.

So the probability of nine males in nine births is

(1/2) ^9 = 1/512 = about 0.195 percent (rounded)