Prince Louis, like his brother, has brown eyes, which is quite curious and indicates that eye color inheritance is not as straightforward as a simple combination of the parents' eye colors. Even though Prince William's parents both have blue eyes, both of their children ended up with brown eyes, suggesting that there might be a strong genetic factor for brown eyes in Princess Catherine's family.

Prince Andrew is a unique case when it comes to his eye color genes. While his eyes are primarily blue-gray, there are varying opinions on their exact shade. Some say they are gray, while others maintain that they are blue. The prince himself has described his eyes as dark blue, which can appear silver or iron-colored in direct light.