The case of the British au pair Louise Woodward, who was accused of murdering a baby boy in her care, has prompted officials to tighten the rules governing the educational exchange programme that brought her to America.
Congress now has added a requirement that young foreign au pairs be trained in childcare and child safety and take a minimum number of educational courses during the year they spend in the United States.
But under pressure from working parents desperate for childcare, law-makers have reversed an earlier decision to raise the minimum age from 18 to 21 and cut the number of hours per day au pairs are allowed to work.
Demand for au pairs has steadily increased to the current 11,000 per year,according to the US Information Agency, which oversees the programme. But the supply has dipped slightly following publicity over the case of Ms Woodward, 19, who was accused of fatally shaking an eight-month-old baby.
Earlier this year came the still-unsolved murder of 20-year-old Swedish au pair Karina Holmer, in Boston. There was also a 1994 case in which Dutch au pair Anna-Corina Peeze, 19, pleaded guilty to child abuse in Virginia, in the death by shaking of her host family's eight-week-old son.
After the Peeze case, the government briefly raised the minimum age for au pairs to 21 and increased the minimum wage from $115 (#163;67) per week to $150 (#163;88). But an outcry from parents managed to get the pay reduced slightly to about $140 (#163;82) per week and the minimum age returned to 18.
More restriction s have been added since the death in February of Matthew Eappen, the eight-month -old Massachusetts baby whose parents employed Ms Woodward. Now au pairs must undergo 24 hours of child development instruction and four hours of infant safety classes, and prove that they have had at least 200 hours of childcare experience, before they can look after children under two.
They may work no more than 10 hours per day and 45 hours per week. And Congress, under fire for having ignored the intended educational purpose of the programme, ordered that au pairs who arrive from this autumn must take educational courses worth six US college credits while in the country.
Agency officials, speaking on condition of anonymity, said the number of would-be au pairs applying from England appeared to be declining.
The au pair programme is an offshoot of the same 1961 legislation that created the Fulbright programme of educational scholarships for students from abroad to come to America. It was formalised in 1986, but an interagency panel and government auditors recommended in 1987 and 1988 respectively that the exchange be discontinued.
By then, however, several organisations had sprung up to administer the programme, with recruiting offices all over western Europe. They were joined by parents in lobbying for more, not fewer, au pairs to be sent.
Eight self-policing private organisations, about half of them for-profit companies, now are certified to run the programme on the government's behalf. They receive fees both from parents and from the applicants, who receive a living allowance while they are staying with host families in the United States under their hard-to-get 12-month employment visas.
Ms Woodward's agency, EF Au Pair, paid for her high-priced legal defence. It also paid for the defence of a Swiss au pair, Olivia Riner, against charges that she burned to death a baby in her care in 1992 in New York. Ms Riner was acquitted.