I'm not sure if gender will really play a part in the upcoming breeding process, no one seems to know! But still, I like seeing some pinks in the sea of blues since there are sooooo many more male-only pets available in game.
Perhaps some of you are naming your pets after something/someone and need a certain gender? Since it was the only female dog available in-game at the time (before Moon Moon came out), I searched for several hours for a rare female Fjord Worg Pup
just to name her after my own dog, Tipsey. Waste of time? Maybe, but it puts a lil' smile on my face
Here is a very helpful chart
to show all male/female/both varieties just in case gender ends up being important to you in one way or another