The second one will most likely be a female. Everytime I have a plant that is slow to show, it is a female. One thing I have noticed, is when growing from seed the plant that looks the best and grows way faster then the rest, tends to be a male. Not 100% of the time though. Sometimes you'll get a super female lol.
If you are growing from seeds that are feminized, watch out for plants that grow, well, retarted. they look completey different from your other plants and sometimes grow in a V split. The weirdest shit you'll ever see. These are usually herms. Never heard this happen to anyone else, but my experience is if it looks retarded, it probably is.