Mother superior

Ely O'Brien picked out a dream outfit for her first Hilary Duff concert: blue jeans, pink sneakers, and a sweatshirt over a Hilary T-shirt. All that was missing were silver hoop earrings.

"My mom never lets me wear them out of the house," sighed Ely, 12, fishing through her jewelry box. "Too big."

Her sister, Crissy, 13, didn't get off any easier. Her mother wouldn't let her leave for the big show on a cold night without gloves. "You are such a parent!" she said, giggling.

"Is that so amazing?" her mother replied.

It is if your mom is also a nun.

Sister Judith O'Brien, a Roman Catholic nun for 24 years and the new principal of St. Ann School in Gloucester, adopted Ely and Crissy four years ago, becoming one of only a handful of nuns in the United States who are both mothers and religious sisters.

Most "Sister Moms" are widowed or divorced women, who entered a religious order after their children were grown, but O'Brien, a native of Swampscott, is one of the few who became a mother after taking her vows. She is the only Sister Mom working for the Archdiocese of Boston.

"She is unique," said Sister Marian Bartho, the archbishop's liaison to the religious orders.

To the students at St. Ann, where she has been principal since June, O'Brien is "Sister Judy," but to Ely and Crissy, she is mom: the woman who drives them around in a minivan and cheers loudly at their soccer and basketball games, sometimes embarrassing them.

"I hate it when she yells, 'Keep your hands up,' " Ely says, rolling her deep brown eyes.

For O'Brien, 49, the call to motherhood came unexpectedly, about six years ago, when she was living on Long Island in a home she shared with Sister Patricia Hartigan, both members of the Congregation of the Sisters, Servants of the Immaculate Heart of Mary, based in Scranton, Pa.

A foster care agency contacted her, looking to place two girls, ages 6 and 8. Within an hour, Ely and Crissy arrived on her doorstep. The girls had never met a Catholic nun, but were happy to land in a safe place.

The two girls were born into a large family, but problems prevented their parents from taking care of them. So they were placed in foster care, staying in several homes before finally being placed with the nuns.

"We had lived in so many places," said Ely, now a lanky preteen. "Some of the people weren't very nice . . . We just wanted to stop moving."

Crissy was pleasantly surprised when she met the two nuns.

"They weren't wearing that black-and-white cape thing. Sister Pat had a pretty skirt on and you had a blue dress on," Crissy said, turning to her mother.

The mother and child bond was instant.

On their first night together, as O'Brien tucked them into bed, Crissy had a special request.

"I asked her if I could call her 'mom,' " Crissy recalled, as she brushed her long brown hair before the concert. "I could tell she loved us. I could see it in her face."

O'Brien's response was an immediate "Yes."

"These two kids needed someone they trusted to call 'mom.' It wasn't going to hurt me," O'Brien recalled.

She was helped by Hartigan, who recently died, and six other nuns who lived next door. Together, the nuns shuttled the girls to school and hip-hop dance lessons, taught them to pray, and read books like "Charlotte's Web," still a favorite.

O'Brien took Ely and Crissy to visit their birth mother each week. They hoped to reunite with her, but she died. The foster care agency asked O'Brien to consider formally adopting Ely and Crissy, who had then been in her care for two years.

"I was floored," O'Brien said, recalling the request. "It's a given when you enter the convent that your life will not include a husband and kids. But as soon as they asked, I knew it was right . . . So I asked permission."

The leadership of her congregation considered the request. A yearlong review of canon law followed. The big question: Would adoption conflict with her vows of poverty, chastity, and obedience?

"The vows really had to be looked at," O'Brien said. "I had a responsibility and a commitment to them, and I still do."

The review found nothing in canon law to stop a nun from adopting. But it was up to O'Brien to prove she could support them financially. The adoption was finalized in a Long Island courtroom, with several sisters looking on in October 2000.

"I would not have been able to do this without the support of my community," O'Brien recalled. "They could have said 'no,' but instead they said, 'We believe you're called to do this.' "

Life as a Sister Mom has been challenging. She's given up convent life at least until the girls are grown, which has made it more difficult to stay active in the life of her congregation. She does her best by attending regional meetings and staying in touch with fellow sisters.

But O'Brien says that mothering has also deepened her vows.

"This has only enhanced my relationship with God," O'Brien said. "Jesus says in the Gospel, 'Let the children come to me.' "

The O'Brien family, including a fat gray cat and goldfish, moved to the North Shore in June, after O'Brien took the job at St. Ann's. They settled in Marblehead, where the girls attend public schools. The family belongs to Our Lady Star of the Sea parish in Marblehead, where Ely and Crissy were baptized, received their First Holy Communion, and were confirmed.

"I think it's healthy to keep work and family separate," O'Brien said, explaining why they don't live in Gloucester. "But I also wanted my girls to grow up where I did . . . surrounded by family."

O'Brien arrived at St. Ann as a sea change swept the Catholic community on Cape Ann. Four parishes, including St. Ann Church, merged last month into the new Holy Family Parish. St. Ann School, founded 120 years ago to educate the children of Gloucester fishermen, kept its name, but is now part of Holy Family.

As a Sister Mom, O'Brien is hardly a traditional nun. But some say she is the perfect fit for a little Catholic school hoping to grow.

"We didn't hire her because she has children," said the Rev. Timothy Harrison, copastor of Holy Family, who led the principal search. "But from a pastoral perspective, I think it helps. She has firsthand experience raising children. As a principal, she knows how to care for a large number of children."

"She's a mom," said Christie DaSilva, 29, a St. Ann alum and parent of a third-grader. "That's huge. When a principal has children, it can make a difference, especially talking with parents. They know where we're coming from."

Having a principal as a mom -- and a nun, no less -- comes with some strict rules, her daughters say. No flashy earrings. Warm gloves are a must. But she also turns a blind eye when they flick their bedroom lights to the boys living behind them. (The code: Two flicks, "We're home." Three flicks, "We're going to bed.")

She limits time in the bathroom and trips to the mall, but they can read Harry Potter and Discover Girls magazine. They can decorate their room with pictures of Hilary Duff, so long as they also think about the words stitched into needlepoint over their beds: "You are God's work of Art."

And just what do they tell friends about their mom? "That our mom is a nun," Crissy said simply. "And they just say, 'Really? That's cool.' "

Kathy McCabe can be reached at kmccabe@globe.com.