The birthrates in Western societies are falling. Why?
General unhealthiness combined with profound hormonal imbalances certainly contributes. A culture of porn does too. But the most important factor is economics. Throughout most of human history, children were an asset because they could labor on the farm or contribute to the family business. These conditions no longer hold. Today, children are a liability. They are prevented from performing any meaningful work and must be supported financially for an ever increasing adolescence. In some cases, they never become self-sufficient. In all cases, they take more than they give.
Once a society has achieved a certain level of technology sophistication, manpower ceases to become the limiting factor. In previous generations, we needed bodies to throw at wars, bodies to throw at diseases, bodies to throw at ships, bodies to throw at farms, and bodies to throw at factories. These are no longer pressing concerns. Automation means that we now need just a few credentialed (not educated!) bodies to throw at laptops. The demand for people is down, and the market is responding accordingly.
Therefore, it is silly to wring our hands about declining birthrates. The true danger lies in having children out of boredom or some misplaced sense of duty. Most refuse to take personal responsibility for their offspring. If government schools and daycares become their de facto parents, we are merely raising another generation of farm animals.