It's amazing that childhood sibling rivalry can continue to adulthood. I was the younger weaker, much smaller sister, who could not stand up for myself against the emotional and physical abuse. My sibling grew very long nails--I bit mine. Needless to say after she would do her teasing about anything she could come up with, we would end up in a physical fight. I ended up with nail scratch marks numerous times on my arms where blood was drawn. My mother reacted as the article stated, and didn't intercede. I remember thinking as a child that one day my sister and I would be adults and we would have a normal relationship and be there for one another. Not so.