>>510684485 (OP)Pay them, starting as young as their father will allow.
First grand is hers as good faith cash. The rest goes monthly into an interest baring dowry account, vested when she births your first child. If at any point she violates the contract (sex, pregnancy, tattoos, meth, etc.) the dowry reverts to the contractor.
Note this works for both marriages and surrogacy while encouraging young women to preserve their virtue and dignity.