If by " normal" you mean the majority, that is more than 50%,then inmy opinion YES it is normal so get used to it.
Our children have decided, that the basis of previous upbringing is to be challenged and by the posts and debates that we have had on AB, seem pleased with 5he results regarding moral issues,discipline and education.
What can you do about you ask?.......Nothing.
Yes as teenager I did joke about sex etc but it was only in male environments, never in the presence of girls.
I don't understand how we have arrived in this socio-economic state but others on AB may have the answers.