Gender: When will I see my baby's parts?

I ran into a couple of pregnant friends earlier today and I began running down the usual tick-list of pregnancy questions:

How far along are you now?
How are you feeling?
Do you have more energy?
When is your next ultrasound?
etc., etc., etc.

By the way, a list similar to this is what signifies that you're in the know with the impregnated crowd. It's like a verbose, drawn out hand shake. The more snobbishly detailed your question, the higher your rank in pregnancy hierarchy. Ask enough and you're qualified to deliver a child.

When I got to the ultrasound question, the pregnant mother said she hoped that she wouldn't be able to see its parts yet because they didn't want to know the gender of the baby in advance. This leads to a question that I have been asked multiple times now, when are a baby's 'parts' visible via sonogram?

At our 10 week ultrasound I personally asserted that what the sonogram tech called an 'umbilical chord' was in fact proof that we were having a boy. However, at the behest of medical science, it was not verified until our 20-week ultrasound. So the official answer is that gender is typically verified by ultrasound in the 18-20 week range.