How can a gynandromorph have male characteristics on one side of its body and female characteristics on the other?

A gynandromorph, also known as a sexual mosaic, is an organism that exhibits physical characteristics of both sexes, often with male parts on one side of the body and female parts on the other.12

This condition occurs due to an aberration in the distribution of sex chromosomes during the very early stages of embryonic development. In many species, such as insects, the sex of an individual is determined by its chromosomal constitution at the time of fertilization. If a mistake occurs during the initial cell divisions of the embryo—specifically involving the distribution of X chromosomes—some cells may end up with a male chromosomal makeup while others possess a female one.23

As the embryo continues to develop, these different cell populations proliferate, leading to an organism where distinct regions of the body follow different sexual developmental pathways. This results in the sharp line of demarcation often observed in these individuals, where one side of the body expresses male traits and the other expresses female traits.2