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.
So much for Abraham, Jacob, and King David....
The USED to be laws against unmarried fornication and adultery (both known as extramarital sex) as well as firm "age of consent" laws that did not make exceptions if both participants were under the age of consent or one ADULT was "near" the age of consent.
Try to get away with selling beer to a 20 year old. That "near in age" won't make any difference in your sentencing.
Same sex sodomy was a crime too. What you ask for WAS the law of land. But when all things homosexual were defined as a constitutional right (argued as acts in private bewtween consenting adults, expanded to minors/adults AND minors/minors, NOT strictly adults, as well as perverts in parks and bathrooms), it did NOT end all sex laws prohibiting acts between consenting adults. Prostitution is still a crime (but babysitting is not, so it is NOT the financial aspect) as is consensual incest (between adults but even between 2 minors should be ok if they are to be consistent). And there was a notable California case of incest prosection between two siblings (not even related) who were 18 and 20 (and had a kid) AFTER the Lawrence v Texas decision. The 18 year old boy was arrested for impregnating his 20 year old "sister".
So either there CAN be sex laws or there cannot.