apparently, you can tell whether your aubergine is male or female from the marking on its bottom. the female will have a round brown one, and the male, a small line instead. this is relevant in terms of cooking because the male fruit, or vegetable as we generally call it, contains fewer seeds than the female, making it the better choice for many dishes. of course, the older the eggplant is (harvested), the more developed and tougher any seeds it does have will be. i'm not sure if this works with all types of eggplant, though.
example of a male eggplant:
almost no seeds inside [this time, at least! i've been duped in the past but it often works — of course, someone may turn around and comment that this is total BS but it's still fun to believe it's true. and hey, here's the proof before your very eyes.... and this was a fairly large eggplant] :