Why not? The age of 18 is an arbitrary cultural norm, I'd ask why the state has to step in and enforce it as opposed to letting the parent or legal guardian decide.

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breezybottom 11 hours ago | parent [-]

Because society has an interest in preventing girls from being sex trafficked by their parents.

	▲	_heimdall 3 hours ago \| parent [-]
		That doesn't track. Sex trafficking is already a crime, preventing the parties involved from getting a marriage license won't stop it. Also its interesting that you are only concerned when the under 18 individual is a girl.