Female lovebirds definitely tend to be more aggressive and territorial, once their hormones kick in. If you can get her away from the cage, to a different room, usually her aggression stops and she will be a sweet pet again. The best way to do this is to stick train her or take her out of the cage with a light towel so she won’t associate being grabbed with your hand. It’s amazing the change of behavior once the cage is out of sight. Males can be better as pets, just because they don’t generally have the cage aggression that the females exhibit. But species and even color mutation can affect temperament. Peach faced are easily the more aggressive and the masked and Fischer’s tend to be more laid back. However, most of the lutino peach faced and Dutch blue peach faced I have known have been exceptional pets. Of course individual personalities are a factor. As for determining sex, unless the breeder had a DNA test run on the bird, telling you the sex was just a 50/50 guess. Size, head shape, pelvic width, etc are not reliable and only seem to be to those who deal with a lot of lovebirds because it always comes down to having a 50/50 chance of being right, so the perception tends to be that the physical signs are reliable.
Thank you for asking Lafeber,