BEDFORD HILLS, N.Y. — Tammy Taylor is worried. It's the day before her release from the maximum-security prison here, and the thought of freedom weighs on her mind.

She's been here before. But as Taylor smoothes her green prison-issue skirt and ticks off a list of things to do--reapply for welfare, visit her probation officer--a new item crops up: arrange day care.

"I'm nervous," she says. "I've been here before, but it's different going home with a baby. There's all this responsibility."

Taylor, 24, entered jail alone, but she's not leaving that way. During her prison term, her son, James Carter, was born. Now a chubby 13-month-old gnawing on an Oreo cookie, James is going home to a world he's never known. Except for his birth at a nearby hospital, this smiling toddler has never been outside the razor-ribbon fences of Bedford Hills.

In most states, James would have been taken from his mother's arms within hours after his birth and placed in foster care if there were no relatives to care for him.

Instead, he has been raised in a prison nursery--one of only three such facilities in the United States.

While these programs--all in New York state--are considered by advocates to be models for the rest of the country, corrections officials still get queasy at the thought of allowing babies to be raised behind bars. When Florida closed its nursery in 1981, one legislator applauded the action, saying: "Jail babies never smile."

That type of talk is heresy to Sister Elaine Roulet, the driving force behind New York's nurseries. A member of Sisters of St. Joseph, Roulet has been working within the confines of Bedford Hills for 22 years.

Her philosophy is simple: "Babies belong with their mothers whether they're in prison or out on the streets. . . . What better person could (they) be with than their mothers?"

Bedford's nursery opened in 1901, but Roulet has brought it into the 20th Century. Very little is left to chance; mothers here are taught to be mothers. These women, many of whom come from dysfunctional families, are required to attend classes where they are taught how to meet the physical and emotional needs of their children. One of the parenting teachers is Bedford's most infamous inmate, Jean Harris, who is serving a 15-year sentence for killing her lover, Scarsdale Diet doctor Herman Tarnower.