It does have consequences, and those consequences can be wonderful or terrible. They can include AIDS and other sexually-transmitted diseases. On a less physical level, sexual choices can transform one's self-image and create, alter, or destroy the most important relationships of our lives. Equally, I think it would be irresponsible to give anything that purported to be wise sexual advice without taking note of the fact that sex has consequences that can mess people up badly, and ways to avoid them. So let's face it here.
Sex involves difficult choices.
Moral choices, and ethical choices. It's easy to get people to agree on that, but harder for people to agree about morals. Misery and suffering are bad. Children are precious, and responsible adults protect and nourish them. There are some other basics that look like morality but are actually ethics.