A gender-neutral term for son or daughter?

I am looking for a term that could be used to describe one's offspring* in a gender neutral manner. Normally, female offspring are called daughters and male offspring are called sons. The three terms are can think of to describe an offspring with no gender are:

• Child - implies an age under that of majority
• Adult child - explicitly states an age over that of majority
• Offspring - unlikely to be used in an informal context ("My offpsring just passed a physics exam")

Is there a single term that can be used to describe an offpsring of no or unknown gender without assuming age, in an informal context?

Sample sentence:

My _______ just passed a physics exam

*I use this term to avoid implying an age (child or adult)

Solution 1:

First of all, I don't agree that child necessarily implies a specific age. But I can see why it might be taken that way.

Asking a senior Do you have a child? wouldn't sound completely natural.

Interestingly, however, asking them Do you have any children? does.

So, for some reason, children (in context) has less of an association with youth than child.

That aside, the most "natural" term, even though not nearly as common, is descendant. Granted, however, it can also apply to grandchildren.

By common implication, heir could also mean a child of any age (although it has a very specific context—and it need not actually be a blood relative or one of a younger generation.)

Solution 2:

It's possible to use both child and kid to include adults (with kids being slightly less formal). Indeed, Mari-Lou A's comment links to the Oxford Dictionary entry for "child" which has a definition:

A son or daughter of any age.
‘when children leave home, parents can feel somewhat redundant’
_{Oxford Dictionary}

Other examples:

As a parent, you might have mixed feelings about encouraging your child to move out.
_WikiHow

Here are five strategies to nurture the friendship during your kids' 20s and beyond: ...
_AARP.org

See also the Wikipedia page for child and the question Referring to adult-age sons and daughters as children.

However, there is ambiguity of "child" also meaning "minor", which we avoid by saying adult child or some variant, such as:

Over a third of these parents said their children cannot afford to live on their own, and more than 77 percent said they don't want their grown children to live with them.
_{ABC News}

However, adult child is slightly suggestive of immaturity (along the lines of "an adult that acts like a child").

Most women/men find this highly unattractive and hence the adult child generally stays single either forever or until they finally do something about their situation and change their life.
_{Urban Dictionary}

It's also possible to circumvent expressing gender by writing e.g.:

My 22-year-old has returned to live at home, and I couldn’t be happier.
_{The Guardian}

Regarding offspring with no gender, we might append agender, such as in:

Full of compassion, love, and many many questions, Libby shares 5 realizations she learned on her journey to understanding her agender child.
_{Genderqueer.me}

where indeed the agender person wrote:

i am:
– agender
– your oldest kid
– they

Solution 3:

Well, you could say, like the old James Thurber cartoon:

"Why, I Never Dreamed Your Union Had Been Blessed With Issue!"

but that's a bit stilted and recondite and, in this context, a joke.

What most people would likely say to people of child-bearing age:

Got any kids?

If the prospective parents are older, you can put it in the past tense:

Did you ever have kids?

It's a fairly innocuous question, not likely to run off the rails unless you happen to tap into some family tragedy: "My wife can't have children. We tried adopting, but ..."