The combination works for ABC's new top-10 hit drama (Sunday, 10 p.m. ET/PT). USA TODAY examines the young doctors of Seattle Grace Hospital — and the actors who play them:

Dr. Isobel "Izzie" Stevens played by Katherine Heigl

Doctor who? A modeling career paid for medical school, but it carries harsh stereotypes. "She's competent and intelligent ... but she doubts anyone would take her seriously," Heigl says.

Actor's vital signs: Performing since her pre-teens, the 26-year-old Washington, D.C., native's roles include My Father the Hero, Under Siege 2: Dark Territory and Bride of Chucky, along with three years as another Isabel on TV's Roswell.

What do you like about your character? "It's probably one of the first times in my career that I've played such a strong female role," she says.

Raising audience awareness: A recent plotline, involving Izzie and an organ donor, hit home. "I work with the Coalition on (Organ) Donation. My personal story is, my brother was killed in a car accident when I was 7. And my parents decided to donate his organs," she says. "Though it is so difficult and such a tragedy, there is a certain grace in being able to save somebody else's life despite the fact that you've lost somebody you love."