Why are all of the Children of the Forest female and all of the White Walkers are male?
Is there a relation between them?
Why are all of the Children of the Forest female and all of the White Walkers are male?
Is there a relation between them?
Regarding White Walkers specifically, my understanding is that they are somehow created by sacrifice of human beings. (This is borne out on the show in the depiction of the creation of the first White Walker.) On the male question, you can look to Craster. Craster sacrifices only male children to the White Walkers. [Note that there is a distinction between "Wights" and the White Walker masters who re-animate them.]
Regarding the Children of the Forest, it does seem as though the TV version only shows females, but @cde 's answer that they are "childlike" and thus "ambiguous" is almost certainly correct.