There comes a time in every kid's life in which a parent sits them down to talk about the birds and the bees...and sometimes, movies beat them to it. Even when the children become adults, it's incredibly awkward to acknowledge the existence of sex in the presence of your parents.
When podcaster extraordinairre Jason Concepcion asked people what the most awkward scene they've watched in the company of their parents was, people shared the memories they were unsuccessful in repressing.
Be wary of films with Leonardo DiCaprio.