What percentage of Jews marry among themselves?

: The accumulation of hereditary diseases in their ranks unsettles many Jews in the USA. They fear discrimination and the ruin of their culture: a bond for survival

The chuppah, the wedding canopy, had already been set up that night. In the early morning the streets began to fill up. Soon those arriving paralyzed half of Brooklyn. The men with fur hats, in velvet dress skirts, silk stockings and patent leather shoes. The women in long dresses, their shaved heads covered with wigs. A few weeks ago around twenty thousand guests took part in the wedding feast of the Jewish Orthodox community in New York. The 19-year-old grandson of the Chief Rabbi Shlomo Halberstam, head of the Bobover, and the 18-year-old granddaughter of Chief Rabbi Moses Teitelbaum, the eldest of Satmar, said yes. "A truly historic event that unites the two most powerful dynasties in the Hasidic world," said Israel Steinberg, rabbi in Brooklyn. Six days and six nights was celebrated. Then the way was free to forge further blood ties between the descendants of the former Polish Bobover and Hungarian Satmar. Not only political calculation and the pursuit of religious consolidation had led to this rapprochement, but also the need for biological renewal. There are a number of scientific studies that give cause for concern to the Jewish communities in the United States. In recent years, several research teams have discovered so-called cancer genes, which are particularly common among the Ashkenazim, the Jews of Central and Eastern European origin. About 90 percent of the roughly six million American Jews belong to this branch of the Jewish ethnic group. The hereditary defects add to the already long list of congenital ailments that are common among the Ashkenazim, but are particularly common among the ultra-orthodox Hasidim. Strict adherence to centuries-old religious rules has resulted in the approximately one million American Hasids representing the most homogeneous group of the Ashkenazi Jews. And even among each other, the individual Hasidic communities have so far hardly mixed. A tradition whose risks are increasingly recognized. An opinion poll by the American Jewish Committee in April of this year showed that as many as 38 percent of all American Jews, including Hasidim, consider frequent intermarriage to be the greatest threat to the continued existence of Jewish culture Study from Johns Hopkins University in Baltimore, Maryland, published by geneticists in the journal Nature Genetics in September last year. The study found that 1 in 17 Ashkenazim had a genetic change that doubled the risk of developing colon cancer. The researchers emphasized that it was the most widespread cancer gene that has ever been discovered within a single ethnic group. Further studies have shown that disease-specific changes (mutations) that promote the development of breast cancer also occur more frequently in Ashkenazi Jewish women. As early as 1994, researchers at the US National Cancer Research Institute had succeeded in isolating such a genetic change called BRCA1. One percent of the 850 Ashkenazi women examined had this genetic defect. A number three times that of the rest of the US population. In a follow-up study, researchers finally discovered a second breast cancer gene called BRCA2. Although this gene was only found in some of the Ashkenazi test subjects, it was not found in any of the non-Jewish subjects. Recently, an Israeli research team discovered a third genetic defect that also appears to increase the risk of breast cancer. It also found that the same mutation appears to make men susceptible to prostate cancer, and this sparked heated debates shortly after the studies were published. Conservative Jewish groups tried to put the results into perspective. They explained that the Ashkenazim are simply one of the most genetically studied ethnic groups in the world. If a particularly large number of disease genes were discovered in them, this does not mean that such mutations were less common in other ethnic groups. In fact, genetic researchers prefer to carry out studies of this kind on subjects who are closely related to one another. Usually, finding disease genes is like looking for a needle in a haystack. However, if the genome of the study participants is largely the same, it is easier to discover mutations in them. For this very reason, geneticists, apart from the Ashkenazim, prefer to study Icelanders and Finns. In contrast to conservative voices, liberal Jewish groups see medical benefits in the knowledge gained through genetic research. After all, Jewish patients were the first to benefit from the new knowledge. However, many of them also fear discrimination. "Anyone with a Jewish-sounding name may from now on be disadvantaged in insurance or in the labor market," warns Amy Rutkin, director of the American branch of Hadassah, the global association of Zionist women. According to Rutkin, companies' fear of absenteeism due to illness could make it more difficult for Ashkenazi women to find a job. To prevent this, Jewish groups of all stripes have been calling for a bill that criminalizes genetic discrimination for months. The research community now also expects clear legal regulations. Because of the discussion about possible disadvantages and the stigmatization of the Ashkenazim, important research projects are stalling. "Fearing discrimination, fewer and fewer women want to take part in genetic studies," reports Marlene Post, President of Hadassah. Scientists at the University of Washington in Seattle have not yet succeeded in attracting enough Jewish women to participate in another breast cancer study, but genetic research should not be blocked right now, according to the Hadassah's official statement. Finally there is the possibility, with the help of science, to speak openly about the accumulation of diseases among the Ashkenazim. So far, fears and shame have prevented the discussion. "When I was told that I had breast cancer, I stopped cooking. The women in the community brought food, we talked, and only then did I hear that many others were also sick," says 45-year-old Orthodox Jewish woman Ellen Passel. Ashkenazi Jews must finally accept that they belong to a risk group for certain types of cancer and other hereditary diseases, demands the Hadassah. This is the only way to prevent the death of many members of these communities. So far, genetic diseases have often been recognized too late. However, early genetic tests and targeted preventive examinations can now save the lives of many people affected.