"The man wants to have a child."
Translation:Ο άντρας θέλει να κάνει ένα παιδί.
I think the issue here is a semantic one. If we mean "to have a child" in the same way as "to become a parent" then I'd assume «να κάνω ένα παιδί» would be right. When I had to translate the English to Greek, I interpreted it literally, as in "to have a child", using «έχω» instead of «κάνω». Might be best to either find a way to explain this or to accept the literal translating supplying the other as an alternative.
The Greek says..."Ο άντρας θέλει να κάνει ένα παιδί." which literally means..."...make a child" which in English is "The man wants to have a child." The Greek is correct and the English is correct. We very often find that literal translations are not correct. The drop down hints show the correct usage of the word in this sentence. Accepting the literal translation which is not the correct meaning would be doing a disservice to the learner.