DIVIDED HEARTS. As the demand rises for flexible jobs to allow mothers and fathers time to be with young children, some employers have found advantages to a part-time professional labor force. But many employers are still reluctant to accommodate workers' changing needs.

JUST before the birth of her first child early last year, Mirelle James took a leave of absence as an attorney for the city of St. Petersburg. Her department hired a replacement, and she was uncertain about plans to return. Nine months later, at the invitation of her boss, Michael Davis, Mrs. James was back at work part time. So was her colleague, Kim Streeter, another city attorney who left to have a baby about the same time.

``They have such a good attitude here about women having children and men having families,'' James says. ``When you come in and tell them you're pregnant, Mike says, `Isn't that wonderful!'''

Mr. Davis explains the arrangement: ``We asked them to come back on a half-time basis for a year. Both were highly regarded, and we were glad to have them back. I haven't seen any problems with it at all. It's worked out well.''

His attitude illustrates the potential advantage of flexible schedules for both employers and employees. Yet only 18 percent of all workers hold part-time jobs, according to Diane Rothberg, president of the Association of Part-Time Professionals in McLean, Va.

Among employed women, nearly three-quarters work full time.

Again and again in recent interviews with mothers around the country, the same plaintive plea arose: the need for flexible jobs to allow parents - mothers and fathers - time to be with young children.

Despite the strong demand, Dr. Rothberg finds ``no groundswell of [employer] interest in part time at the professional level. We see a lot of potential. But there are still a lot of attitudinal problems.''

Those problems range from specific concerns about increased paper work and higher costs to vague worries about inconvenience, lack of continuity, and communication. Some managers, Rothberg says, also claim that ``you can't really be professional and part time.''

Susan Mellini, another lawyer in St. Petersburg, offers an example of that attitude. She worked part time for two years before the birth of her second child.

``The law firm I worked for was very good and very flexible,'' she says.

``But I was told straight out that if I didn't eventually work full time, I'm not serious about my career. My response to that was, `If I wasn't serious about being an attorney, I wouldn't be here at all, because as a working mother you have not one job but two.'''

Even female managers are not always supportive, women claim. ``So many of the influential women who have a large say in corporations don't have children themselves,'' says Susan Anderson of Chicago, a former television anchor woman who is now at home with her two young children. ``They can't really be our allies.'' A recent Business Week survey, she notes, shows that only about 25 percent of women in senior positions are mothers.

``Most women don't want to stay home forever,'' Ms. Anderson adds. ``They want to stay home for a block of time, and then they want to gradually move back in.

``But how do you change the work ethic? Everybody is so proud of it. We wear it as if it's a badge: `I worked 80 hours last week.' We expect other people to praise us and admire us for that. Families are paying a price.

``I don't know why we don't have a more charitable feeling toward parents with young children. We think if we have day-care centers all across the country, we've got the matter solved. I don't think that's the case. We need a better balance in our lives.''

Part-time workers are quick to cite the advantages of more balanced schedules.

``There's a lot of wasted time in an eight-hour day and a five-day week,'' says Kim Streeter, Mirelle James's colleague. ``When you work part time, you learn to budget your time, learn to crank out the work. Without working a full load, it's refreshing when you do get to sit down with your work.''

Julie Harrison, a nurse-midwife and mother of two in Chicago, echoes that theme, saying, ``I feel passionately that part-time people can give a lot, and two part-time people can give more than one full-time person in some instances.

``The work may not be exactly what you had initially. We have to be realistic. But I do think there are jobs in most establishments that would benefit by being shared.''

Still, there are pitfalls.

``Many employers expect you to get five days of work done in three,'' says Gail Manning of Chicago. ``You don't want to work more hours for less money, so you say, `I might as well work full time.'''

Another disadvantage is a lack of benefits: pension coverage, health care, and vacations. ``Prorated benefits are clearly necessary,'' Rothberg says. She notes that Sen. Edward Kennedy (D) of Massachusetts has introduced legislation requiring mandatory benefits coverage for people working at least 17 hours a week.

Some fields, of course, lend themselves to part-time work more readily than others.

``Banking is a relationship business, and you cannot fulfill a relationship in two days a week,'' says Ellie Byrnes, a mother of two who worked for Continental Bank in Chicago. ``In a project-oriented business you can define your time. But in personnel and banking, you have to give service. I never felt I was doing 100 percent of my job.''

The lack of existing part-time positions is forcing some mothers to create their own jobs. ``The 8-to-5 is so unappealing that women will do almost anything to avoid that,'' says a mother of three in Westwood, Mass. She transcribes tapes at home for a nonprofit organization in Boston.

Among her friends, she notes, one started a cookie business, another teaches nursery school, another is a laboratory technician. Others conduct surveys for a marketing-research firm.

``They'll spend two hours of an evening to earn $25 while their husbands baby-sit,'' she says.

For people seeking permanent part-time employment, Rothberg emphasizes the importance of working through professional organizations to increase employer awareness and receptivity. ``There still isn't a recognition by professionals that it's not just their own private concern - that they really do have to join with others to make the point.''

She also notes the value of a proven track record with a company. ``The easiest way is to convert from a full-time to a part-time position,'' she says. ``You are a known quantity to your employer. They don't want to lose you and will make adjustments in your schedule.''

Michael Davis agrees. Despite his enthusiasm for the schedules he worked out with Kim Streeter and Mirelle James, he admits that he's ``not sure I'd do that with someone I didn't know. I knew both of these women and knew they were highly capable.''

In September James and Streeter gave birth to their second babies. After indefinite leaves, both expect to return part time to their jobs in Davis's department.

``If you work at it hard enough, I think you can find a niche,'' says James. ``You see more and more women in many fields working part time, and doing it very successfully.''

Rothberg shares at least some of that optimism.

``We are seeing a considerable change in the character of the work force,'' she says. ``Managers and employers are thinking about what they must do to remain competitive - to lower costs and increase productivity.

``As they think through what they must do to achieve these goals from a people perspective, they will come to see that part-time at the professional level can work for them, either through short-term projects or more permanent part-time arrangements.''

Second of a two-part series. The first part appeared yesterday.

Changes that could help young families

Flexible work arrangements offer important benefits to men and women who want to spend more time with young children. They also help employers to keep trained workers who might otherwise leave.

But many women emphasize that alternative schedules are only one of many changes that need to occur to help families with young children.

Other changes include:

Longer parental leaves. ``As a nurse-midwife I have interviewed many new mothers at six weeks,'' says Julie Harrison, a mother of two in Chicago. ``It is at six weeks that most are expected to return to work. Fatigue is still prevalent. It is the exceptional woman who has reorganized her identity to fully integrate her new role. Six months to one year would be ideal.''

Unpaid leaves, experts say, are not a matter of altruism, but of bottom-line economics. ``It's not going to come out of the `goodness budget,''' says Kathleen Cottrell, a spokeswoman at Catalyst in New York. ``It's cost-effective to put together a parental leave policy to keep her.''

Quality child care at the place of employment. This proximity allows parents to see their children during lunch hours and breaks, and to be readily available should a need arise.

An understanding by employers that either fathers or mothers might need time off to meet children's needs. ``If it isn't recognized that the father may want or need to fulfill such responsibilities,'' Mrs. Harrison says, ``the female employee is seen as more likely to miss work time - and therefore is perhaps the less desirable employee.''

Greater family support by husbands. Women are still doing 84 percent of housework, says a 1986 Johnson Wax survey. A study of 210 Virginia families finds that men spent an average of 1.6 minutes a day on housecleaning in 1986, down from 6.3 minutes a day in 1978.

``Women still carry the majority of the burden,'' says Judy Cole, a mother in Chicago. ``Even though they're out working full time, they're still the one who comes home and makes dinner.''