Oscar the Grouch was orange, Big Bird's plumage was dowdy and Susan's place was in the kitchen - that's how things were when "Sesame Street" first went on the air on Nov. 10, 1969.

The show started its 20th season today on PBS with Oscar a reassuring green, Big Bird sporting beautiful fluffy feathers and a very different attitude toward women."Sesame Street" is shown locally weekdays at 7:30 a.m. and 3:30 p.m. on Ch. 7 and at both 8 a.m. and noon on Ch. 11. It also airs Saturdays at 6:30 a.m. on Ch. 7 and at noon on Ch. 11; and Sundays at 8 a.m. on both stations.)

"The first year our experts told us it was important to show a black family with a strong father figure, so we had Susan and Gordon, a married couple, with her in the kitchen and him shown as a strong male model," said executive producer Dulcy Singer, who was an associate producer that first year.

Now Susan is an independent working mother and Gordon plays the violin and displays a strongly nurturing nature.

"Times have changed and both the men and women on the show reflect that," Singer said.

What has not changed is that the Children's Television Workshop series uses the techniques of Madison Avenue to sell the alphabet and other skills to preschool children from 2 to 5, with special emphasis on the needs of children in low income families.

"The curriculum has expanded enormously over the years," Singer said. "The first season we set out to help a child make the transition from home to school with obvious skills like the alphabet, identifying numbers and letters, relationship concepts, geometric shapes - the things middle class kids pick up at home and know by the time they enter school.

"Over the years we have found children capable of learning so much more, so the curriculum has expanded enormously, everything from Hispanic culture to career awareness, ecology, computers, a special curriculum for disabled children, the whole so-called affective area of emotions."

Singer said the show continues to evolve, changing in emphasis and concept to keep up with the times.

"One new direction we are going this year," she said, "is that almost all our shows will be plotline shows of perhaps seven segments. We were told early on that kids would have trouble following plotlines so in the early years we didn't do it. In recent years, we have found the children enjoyed the cohesiveness."

Another new theme is pregnancy - Maria and Luis, who were married on last season's final show - will become prospective parents and on the season's finale will have their baby.

"We'll show visits to the doctor's office, we'll see a sonogram and, we hope, answer questions preschoolers have about pregnancy."

She said the "Street" will expand its science curriculum in the new season.

"There's also a new adventure series with a character named Blue Bird," Singer said. "Actually, he's a superhero created by Big Bird, who makes up stories in which Blue Bird is the bumbling hero."

Today "Sesame Street" is an accepted part of growing up in the United States - and beyond. The American version of the show is seen in more than 70 countries and there are 14 international co-productions.

Among the guest stars to appear in the new season are Tracy Ullman, Jamie Lee Curtis, Lily Tomlin, James Galway, Kathleen Turner, Susan Sarandon, Dave Winfield and Billy Joel.