Much is starting to be written about the sibling psychology of Tamerlan and Dzhokhar Tsarnaev, the brothers suspected in the Boston bombings.
We are strangely fascinated and fearful at the prospect of criminal siblings.
Jessie & Frank James.
Lyle and Erik Menendez.
The Jonas Brothers.
OK, I threw that last one in to make you smile. Can you do that yet?
In the past week, I haven't felt right about doing anything other than devouring a morbid amount of information about The Brothers Tsarnaev.
In one of the many stories about the brothers was this odd fact about another national tragedy: Six of the 19 hijackers who took part in the Sept. 11 attacks were brothers, each of the sibling teams working together.
It seems simplistic, but a growing body of research has found that siblings can feed off of each other's destructive behavior. Brothers and sisters can be a major influence on our lives, even more so than our parents.
A girl whose older sister is a teen mom is six times more likely to become one, too. Alcohol consumption is twice as likely among kids with at least one sibling who already drinks; for smoking, the risk increases fourfold.
Of course, it seems reasonable to assume that the opposite can happen and our siblings can be a wildly positive influence on us.
The sibling relationship is the longest relationship that most people have in their lifetimes. Approximately 80 percent of Americans have at least one brother or sister.
So we know sibling bonding isn't always a bad thing.
In defense of siblings who have done powerful good in this world, here's the beginning of my list of brothers and sisters who were positive influences on each other -- and us.
- Orville & Wilbur Wright: Thanks to them, we can fly.
- Sarah &Angelina Grimké: Daughters of a rich plantation owner, they became early activists in the women's rights and anti-slavery movements.
- JFK & RFK: The powerful political duo is embedded in American history and the civil rights movement.
- The Ringling Brothers: Five of them liked to have great fun.
- The Bronte Sisters: Charlotte, Emily and Anne brought us imagination, literature and, of course, Lord Byron.
- The Brothers Grimm: Wilhelm and Jacob gave us fairy tales.
- George & Ira Gershwin: They wrote the soundtrack to the Jazz Age.
- The Marx Brothers: Groucho, Chico, Harpo and Zeppo made us laugh.
- Venus & Serena Williams: Two of the world's best tennis players -- and role models.