Depending on the jurisdiction, legal age of consent ranges from 16 to 18 years old. Ask your self do you want to stop young people from having sex or babies? Because you cant stop them from having sex. Comprehensive sex education, support and birth control, will give them the tools they need to make the better choices.
Abstinence alone is a poor choice...Https://www.Ncbi.Nlm.Nih.Gov/pmc/articles/PMC3194801/
Teens who are sixteen years of age and over should be able to have access to birth control without having to ask their parents. They should, however, visit their doctor to find out what form(s) of contraception would be appropriate for them, depending on their circumstances.