I would like to point out impact of having kids. In typical case, kids have much greater impact on many levels of her life, than on his. I have seen more research on this topic, but now I found just a few examples
Anne-Marie Nicot (2009) Impact of parenthood on careers of young men and women read - not original research
Does having children create happiness? read - interesting references included
Also, as has been mentioned in one of papers above:
"Motherhood is seen as a sign of achievement and femininity, while a
man’s accomplishments are viewed through his income and career." (Gore, 2002)
Therefore, I would say that asking a man whether he want or doesn't want to have kids is a completely different question than asking a woman the same thing.
Having this on mind, you can see, how to interpret results in answer of John Pick. Asking men, they have less trouble to reach a decision and hold on to it. It is a serious question, but not quite as much serious, as the same question for women is.
You do not ask a man, if he wants to be pregnant, if he wants to give birth, if he wants to leave his career for some time and then return as woman with kids (means someone who is expected to be worse work candidate because of the household and kids). You also do not ask him, if he wants to have an opportunity to achieve something in the field typical for his gender.
Imagine asking someone, if she wants to have children. And then imagine asking someone else, if he wants his partner to have children. It is not the same question and comparing answers only emphasises this fact.