How about telling them that it’ll lead to exploitation and shame and that birth control will affect naturally occuring hormonal changes during puberty that are supposed to prepare them for the rest of their lives?
And mention that abortion is murder, whether they are capable of bringing a child into this world or not.
Ok. Let’s tell them that too!
They should be told that ultimately “sex” is about children. It brings them into the world; that is its purpose, solely.
For all the birth control, even if you are successful and never conceive with it, you will likely retain “emotional scars” if you will, that will trickle down and affect your actual legitimate children in some subtle way. Such as, pining for the time you screwed so&so instead of their father/mother. A kind of temptation. Or even, just a huge sense of guilt that is “baggage”.
Better to avoid any of those possible scenarios altogether.