Pairs figure skating (and its close cousin, ice dancing) really is unique among sports. In most, men and women take part in separate competitions, usually of necessity. Very rarely, as in the equestrian events, they compete against each other directly, or, as in mixed doubles tennis, side by side.
But only in figure-skating do they fuse into a single entity: every moment of the performance is a collaborative effort. Their roles are different, but complementary — and equally important. That must account for its popularity. There’s a moment just before they start their routine, when the two skaters look at each other: invariably they grin, as if sharing a private joke. It’s like watching a Hepburn-Tracy movie, an idealized vision of relations between the sexes.