So many rules, and are they even necessary?

During my last editing class (or the one before, sometimes the lessons blur together), I learned that we cannot accept the use of the word "their" to connect singular and plural possessive pronouns. This may seem a little confusing, so to simply this rule, here's an example of an incorrect sentence:

Anybody can have their child sing in the local talent contest.

This sentence is incorrect because anybody literally means "any one person" and therefore, we can't use the plural possessive pronoun "their". The grammatically correct option would be to say either "anybody can have his child...." "anybody can have her child...." or "anybody can have his or her child...."

Yet, we can't really choose the option with just "his child" or just "her child" because that would leave out half of the population, so we correctly say "his or her child."

Still, this is a mouthful and it is understandable that someone would want to save time and write/say "their" (see I love saving time, and felt it was necessary to put a slash in my sentence instead of the word "or"). I don't think that people use the word "their" to be grammatically incorrect, but to include everyone and save time. It a way, it's like the word "funner". It's not a real word, but people use it so often, that it has the potential to turn into one. It's used frequently in the vernacular, and so is the word "their" instead of "his or her".

Nonetheless, using the long "his or her" is better than just using "his" which is how the sentence would have been structured in the past. It's good that women have progressed enough in society to be re-included in the English language, so I will gladly use "his or her" over "his,"even if it takes longer to do so.