the difference between male and female seeds is none.that I know of.Only way to tell is to plant them and wait till they show signs of their sex.
You dont need both plants to get a good crop.
autoflowering seeds work by the age of the plant. does not matter what light cycle you have them on. most people I know just leave them under 12/12.
Hope this helps out.
Buck provided an excellent answer. I just like to add a couple things.
2. If you want meds, you want to kill the males as soon as you can. For growing weed, you ONLY want females. If you want to breed, then you do in fact need both male and female. However, by stressing a plant, you might get hermies (male and female flowers on the same plant) that might pollinate itself or other females.
I'd also like to add something that is hearsay but comes from many sources so I will assume it is relieable
1 Female seeds always sprout female. As in feminized seeds these are made by forcing a female to hermy and using it's pollen on a female plant(or just let you're plant flower longer than it's supposed to and eventually it will hermy as a last ditch effort to create seeds but in order to make a mature plant self pollinate and produce viable seeds you have to leave it much longer than you would want to so Just collect the pollen sacks and pollinate your next batch if possible)
2 You can breed without a Male but it's not as effective as selecting the strongest male of a batch and use it to pollinate all the females of the next batch.(turning off any air flow for a day or two and brushing the pollen on specific buds can also keep you from ruining your harvest) Plant seeds from female that had the best qualities. Breeding with just females will cut your gene pool in half.
Autoflower plants are plants that have rederalis genes to make it flower depending on age instead of light cycle, which means if you can control temp and don't mind the extra energy you could flower on 24/24 light cycle though I've seen no evidence that this will increase yield compared to just 12/12(if anyone has seen experiments with this could you point me there I'd love to read it)