In season 3 episode 14 Reese gropes Cynthia. This is after spending the whole episode lying to her and trying to manipulate her into taking her top off for him. After he gropes her she's obviously really angry and upset about it and it was very obviously non-consensual. The whole thing is played off as a big joke in a "boys will be boys" tone and not addressed as actual sexual assault.
In the episode "Cynthia Is Back," a large part of the story revolves around Cynthia, who is 13-14 years old at the time, returning after a long absence. Her breasts have grown in the meantime, prompting Reese to try everything he can to date her so he can see her breasts. Towards the end, he even grabs her breasts, and she beats him up for it.
In the cold open, a character accidentally throws a spider into another character's face while trying to remove it from the house. (You don't see the spider crawling on the person, but you do see it crawling on some pieces of paper when they first pick it up.)
Malcolm loses his virginity to an older woman at Burning Man. He's 17 and she's in her 40's. It isn't really presented as a good or bad thing, just neutrally/up to the audience's interpretation.
The whole show revolves around the family, who have some extremely dysfunctional parenting methods that, by today's standards, would be considered at least emotional abuse.