What is one major cause for differences in infants?

One major cause of differences in infants is genetics. Infants inherit their genes from their parents, and these genes play a significant role in determining their physical characteristics, personality traits, and even their health. For example, infants who inherit genes that code for a certain eye color will likely have that eye color, and infants who inherit genes that code for certain personality traits may be more likely to display those traits. Additionally, genetics also play a role in the development of certain medical conditions and disorders, which can affect an infant's development and overall well-being.