Is it true that if you have sex as a teenager you stop developing and growing?
No, this is not true.
Puberty is the time when our bodies begin to change from child bodies to adult bodies. It can take several years, and usually happens somewhere between the ages of nine and 17. It can take up to 20 years of age for all the changes that happen during puberty to take place.
Having sex does not affect puberty.
Learn more about puberty and your body.