All of my previous EE's are various shades and designs of brown. Now my newest four four-week old EE's are getting white feathers on wing tips and breasts. Please reassure me this doesn't mean they're roos!
Both male and female EEs can be white. If another color emerges, you may be able to sex them by color. If not, you'll just have to wait for the comb/crow/saddle feathers to give it away.
White feather tips alone means nothing. I had 5 EE, three hens and two roos (who were rehomed). All different colors. You can tell the roos by the red patches on the shoulders, among other things. Comb development is also a dead giveaway. One of my favorite EE girls is half white/half orange (this pic is pre 1st molt, her orange is even darker now). That's her EE sister next to her.