Never a word from my parents about sex, maturation, etc. ...until I came out to them at age 36.
As a result, my younger brother has had 4 failed marriages, has been emotionally abusive (and maybe physically) with at least 2 of those wives, and has, thankfully, never had a child.
And my sister, the youngest, was a virgin until age 35, after Mom died. She got married at 40---too late for children (also thankful for this).
The story is actually similar across all of the male cousins in my father's family. The prudish fundamentalist attitudes are completely killing off our family lineage.
I also doubt there is a healthy sexual relationship with any of my female cousins---I actually know of several horror stories among them.