MOST PEOPLE have only one birthday - the one according to the Gregorian calendar. Some people, who also take note of lunar calendar dates, celebrate their lunar calendar birthdays as well, which sometimes coincide with their regular birthdays, and can also be as much as a month apart. Child Holocaust survivor Rena Quint doesn't observe her lunar birthday, but nonetheless has two birthdays - one in December and the other in February. The reason: Until some 25 years ago, she didn't know the date of her real birthday. Quint was brought to America on false papers. They belonged to a child who had perished in the Holocaust, and the little girl's mother, whose relatives in America sponsored her migration to the country, felt sorry for another little girl who had lost both her parents and her two brothers. Soon after their arrival in America, the woman - who had been very frail after her ordeal in the camps - died. Her relatives did not want to keep the little orphan girl and passed her on to a childless couple who gave her a warm, loving home and a new lifestyle. Because she had no papers other than those of the dead child, her new family always celebrated her birthday in February, the date of birth listed on the documents. Quint was already the mother of four grown children when she decided to go to her native Poland with her husband, Rabbi Emanuel Quint, to try to find details of her biological parents and her real date of birth. She discovered that she was actually two months older than she had always presumed. Because her family had always celebrated her birthday in February, she didn't make a big fuss about the December date, but when her friends learned her story, many of them chose to celebrate both December and February with her. Last December, she turned 70, and nobody made a big deal of it because around the same time, two of her grandsons, one from Israel and the other from America, were celebrating their bar-mitzvas. However, unbeknownst to her, a huge 70th birthday party was in the offing. Amazingly, despite the large number of invitees - all of whom were relatives or close friends - the party remained a surprise until the last moment. One of Quint's granddaughters told her that she was making a surprise party for another relative and that she wanted her grandmother to come festively attired to add to the party atmosphere. It was only when Quint and her husband arrived at Kibbutz Ramat Rahel on the outskirts of Jerusalem, where everyone was already gathered, that the penny dropped. An elated Quint went around kissing and hugging everyone, and sat with tears in her eyes as her husband read to her a love poem that eloquently expressed how much she is the center of his universe. Quint's excitement kept mounting as she watched a video prepared by one of her grandsons that showed the highlights of her life - primarily her own wedding, the weddings of each of her children and the weddings last year of her two eldest granddaughters, each of whom will this year make her a great grandmother. Her first great grandchild is due to be born some time between Purim and Pessah, and the second around Shavuot. Quint told her guests that until she was 10 years old, she had never celebrated her birthday, let alone had a birthday party. When she came to live in Jerusalem around two decades ago, she knew hardly anyone. In synagogue, only one person came over to introduce himself - and he, like she, was a new immigrant. She recalled telling her husband that it was just as well that they weren't having any family simha in the immediate future, because unlike the situation in Flatbush, where they had lived before among hundreds of friends, in Jerusalem, they had hardly anyone to invite. This is no longer the situation. Community conscious almost to an extreme, both husband and wife joined numerous organizations in which they were intensely active and continue to be, in addition to which they opened up their home to scores of organizational events, hosting as many as 70 people at a time. Their amazing hospitality is legend not only in Jerusalem but also in the US. It is not unusual for some Emunah leader in America to call Rena Quint and ask whether she can put up visiting guests in her home, or whether she can make her home available for a welcome reception for an Emunah family mission. Quint is also a volunteer guide at Yad Vashem, and a firm favorite with visiting groups from the US, who make a point of asking for her to guide them. She also guides at the David Citadel Museum; volunteers at Yad Sarah and other welfare organizations; regularly attends lessons and lectures on Jewish texts; and is the first to instantly come to the aid of any of her friends who fall ill, lose their keys or have their pockets picked. In addition, she has never forgotten what it means to be alone, and she hosts birthday luncheons and dinners for friends and even chance acquaintances who have few or no relatives in Israel. The little orphan girl, who came to America homeless, friendless and almost inarticulate for lack of education, today has 21 grandchildren, 18 of whom live in Israel. Two of the three who live in America came with their father to be with her on this special day in her life. That was probably the best surprise and the best gift of all. Her three daughters - Menucha, Naomi and Jodi - live in Israel and she sees them all the time. Her son, David, who lives in New York, has work pressures which make it difficult for him to get away. He was in Israel in December-January for the two bar-mitzvas, and she was sure that she would not see him again for months. At the party, Quint apologized to anyone who had been left off the invitation list, "but I had nothing to do with it." Still there's always a chance to rectify such omissions. The Quints will be celebrating their 47th wedding anniversary in mid-March.