Culturally, we're strange.
When it was normal to choose your mate between the ages of 14-18, then restricting sex until marriage was very realistic. Now, many people wait until they finish their education, get a job, buy a house, and coerce their parents enough to pay for an outrageous ceremony before they finally say their "I do's." At that point, humans have looooonnnnnggggg been experiencing the instinct to pair-bond. Not just years, but decades.
The ramifications for expecting older teens and young adults to continue to ignore their sex drives are that we now have a LOT of people who struggle with feeling their autonomy by sexual expression while at the same time feeling shame because of older taboos still subliminally put in place.
The most ideal situation for reconciling biology with culture is through education. We can not expect entire generations to wait until marriage when they are also expected to have a college education and start an investment portfolio (although some virgins have found interesting and kinky loopholes in sexual exploration,
). Comprehensive sex education is the most ethical mandate we can give to our children given our cultural expectations for financial and philosophical autonomy.