They are a little young yet but both have almost no combs and no colour to speak of in their combs. Boys tend to get a blush of pink on their slightly larger combs by around 4 weeks old, and by 6 weeks old their combs are noticeably bigger and redder as well as their well developed, red wattles. The girls combs stay colourless and small until around 10-12 weeks old and their wattles won't start sprouting until then either.
This was the difference between my pekin bantam chicks at a month old:
Young cockerel
Yes a bit young, at this point there is not much development so they basically look like pullets but going off of feathering if I were to guess I'd say the top is a roo and the buff one a hen but all that could change in a week or two