I agree with Marilyn's answer that the man has a higher
probability of having two sons than the woman. However, the probability
analysis that most responses have included assumes that they have no more
than one child in common. The probability for that is less than unity.
How much less than unity depends on information not given (e.g. if the man
and woman are married to each other the probability of having no more than
one child in common is significantly less than unity)......
This reminds me of the old "Monty Hall" problem....
Dr. Mark H. Shapiro
Physics Department
California State University, Fullerton
P.O. Box 6866
Fullerton, California 92834-6866