When One Twin Absorbs Another

Some people are born with parts of an undeveloped twin attached to their bodies. This happens when an embryo fails to fully separate, leaving one twin to physically rely on the other for survival.

This rare phenomenon occurs during early pregnancy when one twin stops developing while the other continues to grow. The fully developed individual, known as the autosite, effectively incorporates the vestigial tissues of their sibling. These extra limbs or organs are entirely dependent on the host body to function. It is a biological quirk that reminds us how complex and fragile the process of human development truly is.