Now that I'm over 35 (but childless), I've taken it as my duty to privately and gently advise younger colleagues who ask that question that there is absolutely

Now that I'm over 35 (but childless), I've taken it as my duty to privately and gently advise younger colleagues who ask that question that there is absolutely no good answer, especially if the person being asked is a woman over 30. My flippant answer: "Well, you can't exactly order them from Amazon..." In my case: yes, I wanted children. The wanting does not always lead to the getting. Any further details from me on this subject might ensure that you never, ever ask that question again, unless you're in a serious romantic relationship with that person.