Yes, there's no rule that pronouns can refer only to humans.

In fact, even the pronoun 'whose' can refer to a thing, as in "The police were unable to identify the owner of the car whose windshield was broken." In everyday conversation, I think many speakers would think that usage sounds funny, so it would be avoided. According to the rules of formal written English, though, it's OK. I think I've even seen it on the GMAT, though I can't recall which example.

Thanks Karen. It is nice to have you on this forum.

I was making this mistake for quiet sometime and now it is clear that pronouns such as they can refer to things.

Will this also apply to all third person personal pronouns such as
they - subjective form
their - possesive form
them - objective form

Thanks.

How about WHO ?

MGMAT clearly indicates that WHO can refer only humans.

schumi_gmat: yes, 'they', 'them', 'their', 'themselves' can all refer to inanimate things.

logitech -- you're right, 'who' can only refer to humans (and 'which' can never refer to humans, by the way). But 'whose' is considered the possessive form for both 'who' and 'which'. It sounds weird when it's used to refer to inanimate objects, though, so many speakers avoid it. But technically, it's OK, and I think I've seen it on the GMAT.