Less than a week into her job as Education Secretary, Ruth Kelly found herself linked to an ultra-conservative Roman Catholic cult and accused of snubbing her “sisters” in Parliament.

As the 36-year- old Ms Kelly was being briefed by civil servants on the Tomlinson report on secondary education, newspaper cuttings were piling up.

Most were incredulous that she had managed to juggle ministerial duties in the Treasury and Cabinet Office with four young children. Others quoted unnamed colleagues asking how she had been so rapidly promoted despite extensive maternity leave .

At a drinks party for education correspondents at the Department for Education and Skills, she admitted being taken aback by the coverage. When asked about her alleged membership of Opus Dei, depicted as a sinister cult in the bestselling novel The Da Vinci Code, she was swept away by Kim Howells, her junior minister.

Andrew Soane, spokesman for Opus Dei, confirmed that the new Education Secretary was in contact with the organisation and had attended meetings.

She is the only British politician he was aware of with connections to the group, which has 500 members in the UK.

Mr Soane said he found much of the coverage of Opus Dei to be “grossly offensive”. “We are not a secret organisation - we’re in the phone book,” he said.

Ms Kelly’s Roman Catholic faith will remain under scrutiny. The Family Planning Association was the first to wade in. It hoped she would maintain the Government’s commitment to tackling teenage pregnancy. Anne Weyman, the FPA’s chief executive, said: “Young people must be informed about all the issues within sexual health, including contraception and abortion.”

Ms Kelly, a former Guardian journalist, was excused the three-line whip in a House of Commons vote on living wills last week. She did not vote on lowering the age of gay consent, or allowing unmarried or gay couples to adopt. However, a department official said Ms Kelly would draw a line between her personal life and policies.

Ms Kelly, who lives with her husband, Derek Gadd, and children in a pair of ex-council flats in Wapping, has said she is the only minister who does not take work home. But she admitted she may have to bend her rule as she prepares for her first speech as Education Secretary at the North of England Education Conference in Manchester next month.

She sends her two school-aged children to a Roman Catholic primary, and said their headteacher seemed unfazed that one of her parents was now Education Secretary. Ms Kelly was privately educated at Millfield’s prep, Sutton high and Westminster school.

Her first school visit in post was to the Charter school in Dulwich, south London, which opened in 2000. She said: “My priorities are the priorities of every parent - raising standards and good discipline so that children can really learn.”

One Sunday newspaper, under the headline “Miaow! Blair babes ditch sisterhood to sharpen claws on Kelly”, carried unattributed quotes from female MPs who said she has done nothing to promote women’s issues.

But Valerie Davey, MP for Bristol West and member of the education select committee, said she would bring a “breath of fresh air, a woman’s perspective and a financial rigour which has been lacking” to the education department.