The problem with that answer is that it excludes heterosexual sex (the responsibility being the resulting human life) but gives full rein to homos, including NAMBLA.
The age of consent should be 18 for everyone. What is the problem with that? We no longer live in an agrarian society where you need 20 kids so you have to start at 15. We live considerably longer as well, so lovers can enjoy each other's company for a lot longer, notwithstanding the wait. Of course over 1/2 of them will be divorced at some point, so maybe that's wrong.
How about this wonderful idea: the complete prohibition of any sexual intercourse outside a monogamous relationship between two persons, exactly one with a Y chromosome, sanctified through holy matrimony before Almighty God. No person should enter into such a relationship without having attained the age of twenty-one years or obtaining a high-school education (diploma, GED, or foreign equivalent). Any extramarital sex shall be punished as cohabitation, fornication, [oral or anal] sodomy, adultery, polygamy, sexual assault, child molestation, rape, or some other felony (in increasing order of severity).
Now enforce it. Excluding the age or education provision, that once served as the law of the land. Then came the Sexual Revolution, then a certain unnamed impeached, disgraced ex-President, who repeatedly sodomized and sexually harassed his own inferiors while committing constant adultery. It almost makes you feel sorry for Hillary.