Identical and fraternal twins: living laboratories
Identical, but not the same: differences between identical twins
Natural experiments: unusual twin types
Developing in tandem: intelligence and special mental skills
Unfolding lives: personality traits, mental disorders and atypical behaviors
Friendship extraordinaire: twins' special relationship
Twist of fate: twins reared apart
Another twist of fate: children adopted together
Lonesome crowd: loss of a twin
Making multiples: new fertility treatments and beyond
Two-base hits and triple toe loops: physical growth and athletic prowess
Noah's art: twins in the nonhuman animal kingdom
The other half: noteworthy twins
Double indemnity: twins in the courtroom
Separate minds in shared bodies: conjoined twins
Double entendre: twinship's many meanings.
