This is a cringeworthy topic and is sure to give a negative impression, unless your son is an exceptional writer. In the event that this is indeed a serious post (given that OP has yet to reply), I suggest reading this thread, which notably makes no mention of the subject your son has chosen. What makes a "good" essay?
You might want to emphasize to your son that typically, essays about sex, mental health, religion, politics, and hot button topics such as abortion are best avoided. Students can and do write about these things, but not many students can do it successfully. Your son’s topic isn’t about sex, but IMO, it is not something that needs to be shared with anyone.