I presume they are budgerigars, and that they are young. Young albino ones are quite hard to sex as their cere is often colourless due to the masking effect of the albinism. When older the c0cks usually get a bluish hue on the cere and of course the hens get a light brownish tint.
The same occurs with the lutino and to some degree with the cinnamons and the best way to sex these type of young birds is to let them nip your finger. The hens bite a lot harder than the c0cks. (I am not making this up, honest)
An experienced fancier can determine the gender of a baby budgie by examining the shape of the head; c0cks have a narrow top of head frontal view and pronounced forehead profile, hens a lower wider top of head frontal view and more rounded profile.