he was known as alex p. keaton on "family ties." that selfishness saved my life. >> it drew in a third of american households every week. his work on the series won him three emmy awards. it's where fox met his future wife, tracie pollen. the couple has been married for 22 years. they have four children. fox's tv success propelled him to movie stardom with the blockbuster trilogy, "back to the future." he followed his role of marty mcfly with 20 films. >> it was on "doc hollywood" where he had symptoms of parkinson's disease. he was in a new role, that of advocate. >> it's a winnable role. >> he works for a quest for parkins parkinson's. campaigning for the cause. his support for stem-cell research has, at times, sparked controversy. despite using his celebrity to point the spotlight in a different direction, he hasn't left hollywood permanently. fox is still a familiar face and a line from his fine episode of "spin city" still rings true. >> it's going to be okay. i'm going to bounce back. it's not over, right? >> it's a long way f

film roles soon led to hollywood, and soon americans got to know him as the young republican alex p. keaton on the popular series "family ties." >> selfishness saved my life. i knew it would come in handy. >> at its peak, "family ties" drew in one-third of american households every week. fox's work on the series won him three emmy awards and a golden globe. it's also where fox met his future wife, actress tracy pollan. >> is that a compliment? >> the couple has been married for 22 years, and they have four children. fox's tv success propelled him to movie stardom with the blockbuster trilogy back to the future. >> marty, you made it. >> yeah. >> fox followed his role as marty mcfly with more than 20 films. >> that's a nice pig you got there. >> that's what they tell me. >> but it was on the set of the movie doc hollywood, where fox first displayed symptoms of early parkinson's disease, which eventually pushed him into a new role, that of advocate. >> the war against parkinson's is a winnable war, and i have resolved to play a role in that victory. >> fox works tirelessly in his quest for a

. >> i am -- i was very alex p. keaton. but that's just me. >> okay, very good, very good.'s almost breathtaking. especially to think back to where the show started. because, it was not a big bang. >> no. >> when it came out of the box. >> no, i always say we were very healthy. we were very lucky that we never went to work feeling like we were on the chopping block of cancellation. the ratings were healthy. but it grew in a very steady rise for the next three years it's been. and i really think it's benefited us. it let us really find a grounding as a cast, just doing our jobs without a bunch of fanfare. >> voices for the characters. >> exactly. so now, when some bigger times have hit, luckily, audiencewise, we're more grounded in the show. and the other thing that's good, is the way the show built had a lot to do with word of mouth. that whole gossip segment. and it's exactly like that. you know, spreading good news from one person to the other about the show. and that's how it built as much as anything. >> 15 million people. >> that's a lot of people. >> right. >> you win

. >>> all right, so if i say alex p. keaton, you know who i'm talking about? michael j. fox.f the inspiring people we talk to in our new series called human factor. here is our chief medical correspondent, dr. sanjay gupta. >> i had the rare opportunity to sit down with michael j. fox for an unprecedented 90 minutes. these long interviews are something he hardly ever does anymore. we wanted to talk about parkinson's disease, talk about his foundation and talk about the numerous obstacles that he has overcome the last 20 years since he was diagnosed. >> a real clear period there in 1993, '94, two years after diagnosis, when i just got it. i just accepted it. and i realized that the world was saying my happiness was in direct proportion of my acceptance in reverse to my expectation. this is what it is, and so now what? >> so, once you were not in denial, you think you were happier? >> yeah, i actually was. when you can look at the truth of something, then that is what it is. it is what it is. now you have options. the only thing do yo have a choice about whether i have parkinso