They have three daughters, Yakarah (married to Arik Attias), Gabriella (married to Dror Rubin) and Amirit (married to David Goodman); and five grandchildren, Imbar, Nieve, Yair (Yakarah and Arik's offspring) and Zohar and Eli-nor (Gabriella and Dror's sons). He is a son of Rabbi Kopul Rosen, as are his brothers Jeremy Rosen and Michael Rosen. Rosen is the honorary president of the International Jewish Vegetarian and Ecology Society. He is a vigorous critic of factory farming, noting that "much of the current treatment of animals in the livestock trade makes the consumption of meat produced through such cruel conditions "halachically" unacceptable as the product of illegitimate means." In addition, he has argued that the waste of natural resources and the damage done to the environment by "meat production" make a compelling Jewish moral argument for adopting a vegetarian diet. He has written extensively on a wide variety of interfaith issues.