In general, the appearance of your abs is due to genetics. There are three major components to abs, which are the rectus abdominis, the linea alba, and muscular bands called tendinous intersections (via Healthline). The rectus abdominis is the main muscle that comprises the abdominal muscles, the linea alba runs vertically down the middle of the rectus abdominis to create the division of left and right abs, and the tendinous intersections run horizontally across the rectus abdominis to create individual expressions of abs. People are born with different numbers of tendinous intersections, which determine the number of abs you can achieve in the gym.
Asymmetrical abs can be genetic, reports Men’s Health. Called staggered abs, an uneven appearance occurs when the tendinous intersections don’t quite line up. While the rectus abdominis is equally distributed on both sides by the linea alba, it’s the tendinous intersections that run horizontally that create the appearance of asymmetrical abs when they don’t run in perfectly straight lines across your abdomen. Additionally, genetics can affect the distribution of body fat. If you happen to have unequal distributions of fat deposits in your abdomen, the result may be the appearance of uneven abs which you might be able to remedy with training (per Healthline).