Why is "co" used instead of "kdo"? Are not boy and girl animate objects, like in English?
In English, if you were asking about someone's new baby, you would ask "What is it, girl or boy?", not "Who is it, girl or boy:, which is completely nonsensical.
Duolingo gives "which", "what" or "that" as translations of "co". "What is that," would be a very rude way of saying it, so "which is that" would be better English unless the Czech is intentionally rude, which I don't think is the intention... so I reported it as a problem
Nothing to do with rudeness. That's just how Czech works - other Slavic languages, too. No need to report it, because it is not a "mistake".
@ JohnFKoen Not all languages are like English. In both German and Czech "the child" is neuter/it, has a neuter article. You do not use masculine or feminine articles, or pronouns, when speaking about a child unless you are speaking about a specific gender. Such as "the girl", "the boy"...
A question why rarely works without digging into the history of random changes in throughout the centuries.
Would "What is it, a girl or boy?" (instead of "What is it, a girl or a boy?") work to as a translation?