On a mid-November afternoon, the women of the United States Senate filed into Sen. Barbara Mikulski’s office to celebrate a sweet 16 of sorts.

With two newly elected women this year — Sen. Amy Klobuchar, D-Minn., and Sen. Claire McCaskill, D-Mo. — the total of women senators come January will hit a record-breaking 16.

Mikulski, D-Md., their dean and the senior woman senator, says she and her colleagues are no longer a rarity, but they still face the challenge of balancing legislation aimed at women with broader issues ranging from national security to the economy.

“When I came . . . we were a bit of a novelty in the Senate,” Mikulski said. “I think what we see now is that we’re not viewed as a novelty; we’re not viewed as celebrities. We’re viewed as senators.”

The slow-but-steady rise in the number of women senators is a pattern that has become commonplace in the last 14 years, but some remember a time when it wasn’t so.

Twenty years ago, when Mikulski became the first Democratic woman senator elected in her own right, she and Nancy Kassebaum Baker were the only two women in the Senate.

“Right now it’s no big deal,” said Kassebaum Baker, a Kansas Republican who served in the Senate from 1978 to 1997. “There will always be women in the Senate.”

Women’s success in the upper echelons of Congress is due in part to the work of people like Mikulski, who in some ways has become their matriarch. The 4-foot-11-inch senator has gained a reputation for encouraging women to enter politics and mentoring them across party lines.

“Barbara has always been very welcoming to new women senators,” said Sen. Kay Bailey Hutchison, R-Texas.

“When I came to the Senate in 1997, Senator Mikulski immediately took me under her wing, as she does for all women senators,” said Sen. Mary Landrieu, D-La., who coined the term “sweet 16” to describe the women senators after November’s election. “. . . I have been inspired by Senator Mikulski’s tireless fight for the people of her state.”

In 1992, when four new women were elected, Mikulski launched bipartisan workshops to familiarize female freshmen with what she calls the “nuts and bolts” of the institution.

“I think she really takes that role very seriously,” said Debbie Walsh, director of the Center for American Women and Politics at Rutgers University in New Jersey. “She’s been very much about the partisan connection, but also the bipartisan connection.”

“Senator Barbara Mikulski has been a leader for women senators from the time she hit the ground running,” Klobuchar said. “She has advice on how to run constituent services — something she does very well — to how to command a podium when you’re under 5-foot-4-inches.”

Mikulski’s efforts to crack the glass ceiling began long before she became senator. A community organizer who mobilized Baltimore residents against a highway project threatening to slice up the city’s Fells Point neighborhood, the young and liberal Mikulski won a seat on a male-dominated City Council in 1971.

“She really had to break in the machine,” said Mary Pat Clarke, who assisted with the campaign. “She went out door to door to beat the machine and get on the City Council.”

The social worker turned councilwoman became so popular in Baltimore that when Clarke ran in