- How are the wife and kid?
- How is the wife and kid?
Which is more correct?
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
As others have mentioned, you shouldn't say "How is the wife and kid(s)." It's neither idiomatic, nor generally considered grammatical in standard English.
"How are the wife and kid(s)" would be considered grammatical, for the reasons Gamileon gave (compound subjects are generally treated as plural).
The most idiomatic way of saying this, though, is "How's the wife and kid(s)" with the contraction "How's". Unlike "How is", "How's" is commonly used with a plural subject. Pedants may call this ungrammatical, but it's a well-established feature of English idiom, and since this expression is fairly idiomatic and colloquial I don't think it's a problem if you use idiomatic but nonstandard grammar.
Check out this chart from the Google Ngram Viewer:
For more information on structures like "How's" with a plural subject, see my answer to the following question: Use of "Here's" before a plural noun
When in doubt, a useful test involves substituting pronouns. Consider
How is they?
How are they?
Say the wife and kid live in different places—maybe the latter is away at school—and you want to express this independence, you might use
How is the wife? The kid?
Any more explicit and the repetitiveness will be tiresome.