What are the differences between male and female kittens at 3 weeks of age?

At 3 weeks of age, male and female kittens may have subtle differences in size and behavior. Male kittens tend to be slightly larger and more active than female kittens. Additionally, male kittens may have a slightly broader face and thicker neck compared to female kittens. However, these differences are not always easily noticeable and may vary among individual kittens.