Hi Chris,
Strict (or at least older) grammarians would not use "their" as a word of indeterminate gender (using "their" only for the plural), but would prefer "his or her." Even older grammarians would use "his" as the indeterminate case, but current regard for avoidance of sexism takes us to "his or her" or "his/her."
Frankly, I think these are both awkward, and agree with some of the latest generation that it is best to use "their" as either the plural or the indeterminate gender, because the meaning will be clear from the context; and, "their" just sounds better to my ear than stumbling over "his or her."
Exactly.
Language is a living, changing thing, usually for the better. Usually. I'm still pissed that we have now officially accepted the wrong pronunciation of "harassment". :gigglemad
However, an example of a good thing is that the prohibition against ending a sentence with a preposition has been abandoned, mainly because it results in unnecessarily awkward sentence structures up with which most people will not put.

