Final answer:
Generally, in the United States and across societies, adult sexual contact with minors and incest are illegal activities. The 'incest taboo' is nearly universally recognized, prohibiting sexual relations primarily between close relatives. While some sexual behaviors may be subject to local laws and cultural norms, there are common standards like the incest taboo which are widely enforced.
Step-by-step explanation:
All states vary but generally, adult sexual contact with minors is illegal, as well as any kind of incest. The term 'incest taboo' refers to a prohibition against sexual relations that is universal between parents and their offspring and sometimes extends to other relations considered too close for sexual relationships. This social norm is present in virtually every society and culture, even though the specifics of which relatives are considered off-limits for sexual relations can differ.
Moreover, there are various laws and social norms governing sexual behaviors, such as the age of sexual consent, premarital sex, and homosexuality. While some behaviors are regulated more strictly in some places than others, certain norms, such as the incest taboo, are widely understood and enforced across the globe.