Miriam and Beth Goldstein are used to being mistaken for one another. At times, the twins have been able to take advantage of their physical similarity. They talk about a time when they shared the same gym membership during the summer in their home in Israel.

"We were only there during the summer and it was very expensive to just have a membership for three months," Miriam says. "We worked it out so Beth would have the ID in the morning and I would have the ID late at night."

But there were some complications to the ruse. Miriam knows Arabic and would often stop to talk to other Arabic-speaking patrons. Beth does not and would often have to fudge her way through conversations with her sister's acquaintances.

"I learned one phrase in Arabic that I could use: I have no time right now," she says, laughing, "so I could get out of talking to them."

"I had to stop speaking Arabic because it would incriminate Beth," Miriam says.

Switching roles has been a way of life for the Goldstein twins, in more ways than one. At Harvard, Miriam chose Near Eastern Languages and Civilizations, and Beth chose Biochemical Sciences but in high school in Tampa, Fla., Beth says, "People thought Miriam was the science person and I was the humanities person."

They were so sure in high school that Miriam would go into the sciences that Beth tried to convince her to go to MIT instead.

"I'd come to visit Harvard and I loved it, and I didn't want Miriam to be at the same place, but I wanted her to be nearby," Beth recalls. "So I spent a lot of time trying to show MIT in the best light, by taking great pictures of people biking around MIT and of the campus."

Her campaign failed but both Beth and Miriam say they are happy with their decision to attend Harvard together. Similar in academic strength and extracurricular interests, they say their Harvard experience has been one of complementary, rather than competing, roles.

Take their involvement in Hillel for example.

"Since there were two of us, the effect we had [on Hillel] was increased. It was more than just doubled, it was almost exponential," Miriam says.

Beth served on Hillel's steering committee, as well as on other activities committees. Miriam has also been involved with Hillel, was co-chair of Harvard Students for Israel and the founder of the Harvard Israeli Dance Troupe.

And for the past year, they have shared a double room in Adams House, much as they did at home, after living apart for their first three years of college.

They were placed in separate first-year dorms: "[The administration] clearly tried to separate us in Matthews and Hurlbut [Halls]," Beth says.

They joined different blocking groups that went to different Houses: Beth to Adams and Miriam to Currier. But for the last year, they decided to room together once again. It has been an experience that has made them closer than ever, they say.

"We sleep in the same bedroom and eat almost every meal together," Miriam says. And while they pursued different academic paths, both have been successful students, making the dean's list all semesters and graduating with honors. Miriam has been inducted into Phi Beta Kappa and won a Hoopes Prize for her thesis.

While they currently share their Adams House quarters, graduation will put several time zones between them. Miriam will be studying Jewish and Arab literature at Cambridge University next year as a Marshall scholar, while Beth will begin medical school at Hebrew University.

The sisters' commitments to their religion and to the Jewish community are something that both have strengthened over the years. They grew up in Tampa, where their father worked as a doctor and their mother as a homemaker, but after they came to college their family moved to Israel, where Miriam and Beth now spend their vacations from school.

"We were the ones who stopped them [from going] 20 years ago and we're the ones who brought them [there] 20 years later," Miriam says.

Their parents, who were strong Zionists, had been contemplating a move to Israel before Miriam and Beth were born, but put off plans once they learned they were having twins. Their family later decided to move after visiting the twins who were participating in summer programs in Israel.

And while their careers will now diverge even more, Beth and Miriam share a commitment to improving social conditions in Israel.

Miriam hopes to explore the connections between Jewish and Arab culture at Cambridge and plans to pursue an academic career in this field.

"Whatever I do, I want to teach," she says.

Through these studies, she believes she can promote better understanding between Jews and Arabs in Israel.

"We share a culture. There's just a different religion," Miriam says. She became interested in the subject after spending a summer during high school learning Arabic in a Jewish-Arabic village in Israel.

"There's cultural coexistence in Israel now, you just don't hear about it in the evening news," she says.

Beth hopes to use medicine to impact social conditions in Israel. She plans to become a gynecologist and work with ultra-conservative Jews and Arab patients.

"By interacting with these women, I can bridge the gap between dominant group and the minorities [ultra-orthodox Jew and Arabs]," she says.

She also wants to learn Arabic. "I'll be able to have a deeper relation to my patients if I can speak their language," Beth says.

"There's a real need for female gynecologists in Israel, there are very few right now," she adds. "Women can relate to each other on a basic level."

Beth and Miriam say they are not sure how their paths will intersect in the future. Beth says she definitely wants to live in Israel, Miriam is not as sure. But both agree that their shared experiences at Harvard have helped strengthen their relationship.

"Everyone always says one of the best things they do at college is making a large group of friends," Miriam says. "But one of the most valuable things I'll have done is to make a closer relationship with the closest friend I'll ever have."

She turns to Beth and laughs. "That's you."

"Well, thanks," Beth smiles. "I agree."