I think you could probably do a search on this topic and find lots of threads because I know I've jumped in on quite a few. My big concern is people having two young females that are very close in age. From what I've seen, this frequently doesn't work out.
Sometimes people want females because they think they are sweeter, more "maternal," more petite, etc. They might be a bit smaller than the boys so that one's not a fallacy, but in my experience the boys are often more easygoing and affectionate. Don't tell my Lucy I said that! What I do know is that if the girls start fighting, they will not stop.
I have a female Boxer and one of my current fosters is a female. She (the foster) is very sick (nothing contagious, though!). When I brought her into my home I held my Lucy's jowls in my hands and said, "Lucy, Star is very sick. Please don't give her the business, okay?" And much to my relief, Lucy's hackles didn't even go up and she let Star into our home with no problems. Usually, though, it can be a bit tense having a bunch of girlies around. You could not pay me to have two females in my home permanently. One Lucy Goose is plenty.
Claudia
Green Acres Boxer Rescue of WI