Genders

Hello everyone.

I was wondering about a conlang I'm sketching down. I'd like to insert a
male-female gender distinction. How would this happen? In which gender would
inanimate objects go? How do Arabic and Hebrew treat inanimate objects,
plants, flowers, animals ? Is each category tied to a special gender, or is
their ending to determinate it? What distinction could there be between male
and female in the oldest stage of the tongue? PIE seems to treat female
nouns as a inanimate plural (but I'm sure feminists would rather call it 'a
group plural' : ). How is the whole thing in PSemitic?

And about a IE-like 3-gender system: is it common, or a peculiarity of our
language-family? Are there other families with this kind of gender system?

Luca