This flag thoughtfully takes the 'traditional binary' pink and blue to express the 'trans' part of gender.
The flag consists of 5 stripes: two light blue stripes, the traditional color for baby boys, two pink stripes for girls, with a white stripe in the center for those who are transitioning, who feel they have a neutral gender or no gender, and those who are intersex.
Of course, way back before color-fast dyes were available, all babies wore white regardless of sex or gender because messy baby clothes needed to be cleaned with bleach! If you look a bit deeper, pink babies were seen as healthy and strong, whereas babies with a bluer skin tone were seen as weaker -- so blue had been associated with girls and pink with boys, until marketing gurus decided that a codified gender color pallet would mean families couldn't use hand-me-downs as readily when having both baby boys AND girls.