Picking an age range or sex of children to foster

We are in a similar position, but with two bio girls. We have been debating back and forth about only taking boys. We are open to any race (I think we have some misgivings, but it's hard to know how it will really be!) but have a young age range because of the ages of our bios. We don't have our heart completely set on boys, and sometimes I could see another girl fitting in really well. I think we are going to leave it up to God's direction at this point, and see who needs us. If we ended up adopting a girl, I could see us continuing to foster boys with the hopes to adopt one more. But we will see! :)