1 doctor weighed in:

Why can siblings be so different in temperament?

1 doctor weighed in
Dr. Jeff Jacobs
Pediatrics - Psychiatry

In brief: Many reasons

Sibs share, on average, 50% of their genes with one another. The actual percentage in a specific family may be significantly less than 50%.
Further, although there is a tendency to think siblings are raised in the same environment, that's not really the case. Birth order makes a difference. Parents interact differently with each child. One child may have been exposed to a depressed mother, etc.

In brief: Many reasons

Sibs share, on average, 50% of their genes with one another. The actual percentage in a specific family may be significantly less than 50%.
Further, although there is a tendency to think siblings are raised in the same environment, that's not really the case. Birth order makes a difference. Parents interact differently with each child. One child may have been exposed to a depressed mother, etc.
Dr. Jeff Jacobs
Dr. Jeff Jacobs
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