People with anxiety disorders such as OCD know that nothing can be more paralyzing than having too many options. Go to a store to buy a sweater, find four that you like and the odds are pretty good you'll stare and stare... and buy nothing at all.

Science has yet to isolate the Godiva Chocolate or Prada gene, but that doesn't mean your weakness for pricey swag isn't woven into your DNA. According to a new study of identical twins, it's less TV ads or Labor Day sales that make you buy the things you do than the tastes and temperaments that are already part of you at birth.

Marriage is a lot of things - a source of love, security, the joy of children, but it's also an interpersonal battlefield, and it's not hard to see why: Take two disparate people, toss them together in often-confined quarters, add the stresses of money and kids - now lather, rinse, repeat for the rest of your natural life. What could go wrong?

Since narcissism is fueled by a greater need to be admired than to be liked, psychologists might use that fact as a therapeutic lever - stressing to patients that being known as a narcissist will actually cause them to lose the respect and social status they crave.

We're learning how important it is both to preserve sibling relationships if they work and repair them if they're broken. We're also learning a lot about nonliteral siblings - stepsiblings, half-siblings - and the surprising power they can have.

The truth, of course, is that the only necessary and sufficient condition for human beings to murder one another is the simple fact of being human.

Sisters have ways of socializing brothers into the mysteries of girls. Brothers have ways of socializing sisters into the puzzle that is boys.