des enfants ...

[Billy Bosworth]

If I am asking if a couple have children, I might say "ont-ils des enfants". (ie. plural - children). 

I my book I noticed the following: "... ils n'ont pas d'enfant". I am OK with the use of "de" after a negative, but should it be "enfants" (plural) or is this a rule/anomaly/typo?

(I did ask a Frenchman, but he couldn't say with 100% certainty; his "guess" was "enfants").

[George Hunt]

Yes I think both would work :

." ils n'ont pas d'enfant" as well as . "ils n'ont pas d'enfants".

A slight difference and I suspect the latter would be more usual.

[Stevo]

Hi.

Here a clear answer about this typical French question.

Never French people ask “avez-vous un enfant ?” ( “Have you just one child?” ). the tacit tradition is always to ask about several children. So, that’s why the ritual question is : “Avez-vous des enfants ?”

And like French people answer : “non, nous n’avons pas d’enfant.” (“No, we haven’t children.”), the grammar and the spelling are okay.

Why ? because, zero child is equivalent to the singular shape by default. It’s also the same situation for the usage about the word “aucun” ( no one, none, nobody ).

Zero or no child = singular
One child = singular
Two children and more... = plural

Consequently,

- “Avez-vous des enfants?”
- “Non, nous n’avons pas d’enfant."
 ( “Non, nous n’avons aucun enfant.” )

Finally, to answer correctly at the George’s question, according to the real usage about the French tongue of the street. Yes, sometimes, French people also use the plural shape instead of the singular. It’s an error, but it’s very common...