Can parents with single eyelids have a child with double eyelids?

No, it is not possible. If both parents have single eyelids, the likelihood of their child having double eyelids is extremely low. Single eyelids are determined by a recessive gene, while double eyelids are controlled by a dominant gene; therefore, if both parents have single eyelids, they cannot have a child with double eyelids. However, certain environmental factors may influence the development of double eyelids, such as malnutrition, lack of sleep, or exposure to radiation. If these environmental factors cause changes in the child's genetic expression, it might be possible for the child to develop double eyelids.