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Odd Friendship, perhaps.
In Star Trek: Deep Space Nine, two boys become friends because they are the only two about the same age. Their cultures are quite different and they have different backgrounds. Each boy has a single father, and both fathers disapprove of their becoming friends and spending time together, at least until Character Development.
I checked the characters page and someone listed it under Odd Friendship, which works for me.

Two characters are friends, but there's drama because their parents don't approve of the friendship for whatever reason.