Which parent combinations yield only white offspring?

To yield only white offspring, both parent organisms must carry the alleles for white coloration. In genetics, if white is a dominant trait, then a combination of two homozygous white parents (WW x WW) or a homozygous white parent (WW) with a heterozygous parent (Ww) will produce only white offspring. If white is a recessive trait, only two homozygous recessive parents (ww x ww) will produce exclusively white offspring.