Really? That sounds worse to me...

"How old are they?" "When did you have them?" "Are they a boy or a girl?" "They are adorable."

I would probably just drop the pronoun completely.

"How old?" "When did you give birth?" "Boy or girl?" "So adorable!"

>"How old are they?" "When did you have them?" "Are they a boy or a girl?" "They are adorable."

Those sentences sound completely normal and grammatical to me.

'They' is fine as a singular, for instance the person that you have just replied to, they say that you are completely wrong, and I agree with them. See?

Look up the "epicene they".

If you say "how old is they?" or "they is adorable" it will sound cooler, like you're speaking some sort of patois.

I just read this fun Wikipedia article for language nerds:

http://en.wikipedia.org/wiki/Singular_they

That's pretty cool. The verb conjugation for "to be" seems to be actually useful in this context. It sounds a little wrong to me, but that's just a matter of habit, and it would probably flow better in written English than writing he/she.

You're in dangerous territory if you ask boy or girl - people often assume their child's gender is as obvious to you as it is to them. I've gotten some unexpected hostility from strangers this way.

"How old is your child?" "How old is the little one?"

When pronoun is unknown, "they" is the common choice. At queer conferences it is becoming the practice to include preferred pronouns on your name tag.

well, it is highly dependant on the language, some require distinction between sexes, and using a gender neutral term is sometimes offensive.