Parental dating and child attachment
It is known that both nature and nurture figure in development; researchers are attempting to ascertain just which one plays the larger role. There are two types of twins: identical and fraternal.Identical twins have exactly the same genes; fraternal twins are no more similar than regular siblings.
In most societies throughout the world, siblings often grow up together, thereby facilitating the development of strong emotional bonds.In law, the term consanguine is used in place of agnate).They share only one parent instead of two as full siblings do and are on average 25% related.In the case where the unshared parents are identical twins, the children share as much genetic material as full siblings do.
In this case, a woman has children with two men who are father and son, or a man has children with two women who are mother and daughter. Furthermore, the two offspring will have an aunt/uncle-nephew/niece relation.
However, the same is also theoretically possible for full siblings, albeit (comparatively) much less likely., to total strangers.