A few basic points should be made clearly right from the start:
1. The Church is not obsessed with sex; The Church has an obligation to address all aspects of human life, and it so happens that humans are often preoccupied or obsessed with sex.
2. Sex before marriage (fornication) is morally wrong.
3. Living together before marriage (cohabitation) is morally wrong, and for two reasons:
a. it creates an extraordinary amount of temptation for fornication. (Why subject yourself to temptation if it is not necessary?)
b. it presents a false impression of the nature of the relationship (scandal) or discredits the Church as an effective moral guide.
4. Contraception is morally wrong.
5. Sex is Good in the context of a sacramental marriage because it supports the unitive and procreative ends of marriage.
We will continue to explore these concepts later on in the semester, but commit these main ideas to your understanding.