A NEW breed of nanny now in vogue in the United States is called an au pair, from the French ``on a par with.'' She is America's version of Mary Poppins: young, foreign, often attractive, and sociable. She makes breakfast for the children, sees them off to school, accompanies them to the playground and gymnastic lessons, M.C.'s story hour, checks their homework, bathes them, and tucks them into bed. She's not a servant, but a participating member of the family.
And she's the answer to the prayers of dual-career professionals and families, wealthy enough to afford the luxury of live-in child care. PETRA RAADTS is a 20-year-old au pair from Oss, a small town in the Netherlands. She always wanted to visit the US, but never could save up enough money from a waitress job to pay for the trip.
When Petra saw an ad in her October, 1987, hometown newspaper for girls to go to the US under the auspices of The Experiment in International Living's Au Pair Homestay Program, she rushed to apply.
Two months later, she arrived in Washington, D.C., for a three-day orientation with 120 other anxious and eager young women from the Netherlands, England, France, Germany, Switzerland, and Denmark.
``I couldn't believe my eyes,'' was Petra's reaction to seeing her American family's home for the first time.
Set back on an acre of professionally manicured yard was a large New England colonial house with five bedrooms, four-and-a-half baths, paneled library, and even luxuriously finished basement.
Petra's living quarters, located in a separate wing of the house, consisted of a tastefully furnished bedroom with its own telephone and small television - and a bath.
Here she has been living with an ambitious and successful suburban Boston family for seven months. The father, a partner in a prestigious Boston law firm, works long hours. The mother, a full-time law student at Harvard University, needs high-quality child care for their two children, age 10 and 3, while she finishes her degree.
Well settled in and working 45 hours a week, Petra cares for the children and does light housework. She has developed an array of activities - from paper cutting and pasting to chalk drawing on the driveway - to amuse the preschooler. She has been learning to play baseball and a number of computer games with her 10-year-old charge. AFTER seven months of full responsibility, Petra sounds like an expert in child rearing. She remarks that American children have so many choices that do not exist in Europe - about the food they eat, the clothing they wear, and the activities they want to be involved in.
But some American parents are not teaching their offspring to fully appreciate life, according to Petra: ``Oh, they take so much for granted. Nothing excites them. They have too much.''
America's reputed insistence on having the best and biggest seems evident in its offspring, Petra comments further. She feels that competition, even among 10-year-olds, is fierce - that parents push their children to excel in schoolwork and athletics.
In checking 10-year-old Jonathan's homework, Petra senses the pressure he feels to perform in class. In the Netherlands, most 10-year-old children do not even get homework.
Petra does not find the American way totally flawed, however. On the dimension of creativity, expressiveness of feeling, and flexibility, she gives it much higher marks.
She also approves of the candor and friendliness of most Americans.
Europeans tend to be more formal, she says. PETRA is one of about 120 legal au pairs in the Boston area. The Experiment in International Living - one of two pilot programs sanctioned by the US government - brings au pairs to this country for one-year stays. It currently has over 1,200 au pairs working in the major suburban areas of the East and West Coasts.
By hiring a legal au pair, families are protected from stiff fines imposed when the Immigration Service finds out about an illegal alien.
Since the program is a cultural exchange, families do not have to deduct Social Security or income taxes from what they pay their au pair. Both the au pair and the family benefit from having an organization behind them, should problems in the relationship develop.
Petra says au pairs receive transatlantic air fare, a weekly allowance of $100, and a $300 tuition subsidy toward courses of their choice. Since her English is already quite good, she is taking a business English for foreigners course, as well as an aerobic class.
One of the advantages of being part of the family is the chance to share family vacations. Petra has visited Maine's Mount Desert Island, Stowe, Vt., and Florida's Disneyworld with her family. A trip to Aspen at Christmas was scheduled as well.
``There is so much to see here,'' Petra exudes.
On her weekend-a-month off, she and au pair friends travel on their own. New York, Washington, and Atlantic City have been favorite destinations.
Au pairs, on their limited budgets, are very adept at finding inexpensive means of seeing the US. For example, staying with au pair host families in other cities is a popular practice.
In all, Petra feels the program has been a success for her, and that this has been a time she'll never forget: ``I've matured so much. Learning to deal with new people, strange people, has given me more confidence.''
She has become very fond of her American family and knows she will miss them when she has to return to the Netherlands. Being treated as part of the family is what she has most valued in her months here.
However, a year is plenty of time to be away from home, she feels: ``My life has just been so different here.''
Will there be a next time?
With a twinkle in her eye, she dreamily says, ``Well, maybe Australia.''