I think Maureen McCormick has one, Barry Williams and Mike Lookinland have two and Susan Olsen has one, I don't think Chris Knight or Eve Plumb have any and I'm not sure about Robbie Rist.

Barry Williams - 1 son
Maureen - 1 daughter
Chris-????unsure
Eve- I do not think she has any.?????unsure
Michael - 2 sons
Susan- 1 son.
Ann-I do not think she has any.????unsure
Florence- some sons
Robert - one daughter.
Robbie- I do not think he has any.?????unsure

Julian's:
Barry Williams - 1 son
Maureen - 1 daughter
Chris-????unsure NO CHILDREN
Eve- I do not think she has any.?????unsure NO CHILDREN
Michael - 2 sons
Susan- 1 son.
Ann-I do not think she has any.????unsure NO CHILDREN
Florence- some sons 4 CHILDREN; I THINK 2 DAUGHTERS; 2 SONS
Robert - one daughter.
Robbie- I do not think he has any.?????unsure

I thought you meant the characters. I know in one movie Peter didn't have any. I can't remember what the last tv series involved. I did read that one of the actors on Home Improvement played a son.

In the follow-up movies/sequels, Marcia had two children, Greg had one, and Jan had an adopted one. The other three didn't have any kids.

Jonathan Taylor Thomas from "Home Improvement" played Greg's son Kevin in "The Bradys" (the six-episode series from 1990), although he didn't play the role in "A Very Brady Christmas".