"Is it true that a female eggplant has more seeds and is therefore more bitter than male eggplant?"
Everyone is quick to blame the female! I have to first point out that technically, there is no such thing as a male or female eggplant. Eggplants are, botanically speaking, a fruit: like their brethren peppers, tomatoes, cucumbers and squash they are produced from a flower -- specifically, when male pollen is transferred to the female parts of the flower. They resulting fruit is sexless.
But they do become bitter with age, and like humans, tend to get dull, wrinkled and less taut skin the longer they are around. Pick an eggplant that is glossy, heavy for its size and free of brown patches and bruises. When you press it with your fingertip, the skin should bounce back, not stay depressed. Eggplants are highly perishable, so buy it no more than a day or two before using.
Recipe: Seafood Stuffed Eggplant