Violence Sims can get in fights with each other, as well as hit and yell at each other if they are mean enough, or angry at each other. The fighting is represented by a spinning dust cloud, obscuring the fighting Sims. There is no blood or gore to speak of.
Sims can die in various accidents, such as by electrocution if they use faulty appliances. Their deaths are comically exaggerated and cartoonish.
Sex & Nudity There is no nudity in The Sims 4, though Sims can appear in their underwear (bra and panties for women, boxers for men). Players can adjust the Sims' chest size as well as butt size for both male and female Sims.
Sims can romance each other, with such options as flirting, kissing, hugging, etc. Sims can have sex; in the game this is called "WooHoo" and is represented by the Sims getting into bed together and giggling and talking while the bed covers move. It's not graphic so much as silly. Sims can also "Try for baby" and get pregnant.
Strong Language There is no swearing in The Sims 4. All the Sims speak a made-up language called "Simlish." Some of the humor could be considered crude; if the Sims don't get to the bathroom in time they can urinate on themselves, for example.
Substance Use There is no substance use in The Sims 4. Sims can go to a nightclub that serves drinks that appear to be non-alcoholic. Some have names that parody real mixed drinks.
Consumerism The Sims encourages players to buy nicer furniture for their Sims (cheap things break more easily, and make Sims uncomfortable). The previous Sims games have had multiple expansion packs with additional content, which players are encouraged to buy.
Discrimination The Sims 4 allows incredible body diversity as well as racial diversity. Sims can be any sexual orientation--it's all up to player choice.