Among the many difficulties I had with high school Latin was trying to accept the notion that some words are masculine, while others are feminine. Why should captivus (prisoner) be masculine, while casa (house) is feminine? It made no sense to me.
In English we retain some of Latin's gender suffixes in names (Julius, masculine; Julia, feminine, for example), but thankfully, most English words are neither masculine nor feminine, and when speaking or writing, we need not worry about gender. That is, until we get to pronouns.
When you begin a sentence like this, "If someone is looking for a new car ...," what personal pronoun should you use to finish the sentence? When I was in school, I, like everyone else, was taught to use the masculine pronoun: "If someone is looking for a new car, he should ..." Thanks to the women's movement, this is now widely perceived as sexist, as if it implies that only men look for new cars. Today most people would say, "If someone is looking for a new car, they should ...," never mind that it uses a plural pronoun to refer to a singular noun. I've heard women, when clearly referring to an unspecified man, use the word they, as if any use of a masculine pronoun, even when talking about men, is sexist.
Some writers, as if trying to right past wrongs, always opt for a feminine pronoun: "If someone is looking for a new car, she should ..." When I come across this, I always want to look back at the previous sentences to discover what woman is being referred to. Usually there isn't one. The writer wants to avoid the appearance of sexist language and so become blatantly sexist.
Other writers, trying to be more evenhanded, alternate between he and she or him and her. This can really get confusing. My respect for a writer always goes downhill quickly whenever I see such flip-flopping.
For myself, I have three guidelines I try to follow, and I would recommend them to others:
1. Whenever possible, rewrite sentences to avoid having to use either a masculine or feminine pronoun. This can be done easily in most instances. Example: "Anyone looking for a new car should ..."
2. The phrase "he or she' can quickly become burdensome for both writer and reader if it is overdone, but sometimes it is simply the best option available. Don't be afraid to use it sparingly.
3. As a last resort, just use the masculine pronoun and be done with it. A little harmless sexism is better than either confusion or bad grammar, if you ask me.