Drive On

RANCHO MIRAGE, CALIFORNIA | She came off the green all smiles, the kind of genuine beam that lights up an already bright California day.

You could understand it on Thursday. After all, Ally McDonald of Fulton, Mississippi, had never led after any round in her three years on the LPGA Tour. To hole a birdie putt at dusk on the final hole in the final group of the opening day to lead a major, long after anything resembling a crowd had vacated Mission Hills Country Club, obviously generated a satisfied grin.

But on Friday the smile was bigger even though her lead had vanished. That’s because the even-par 72 that followed her opening 68 was harder, the circumstances newer, the round tougher. McDonald had to dig deep in the second round when everyone expected her to fold. And she did, not for herself, but because she plays for something more, something few even know that epitomizes the LPGA’s new theme of Drive On.

McDonald has type 1 diabetes. She still injects herself with insulin and wears a monitor throughout the day. At the AN...