Gypsies living a traditional way of life follow strict rules of sexual behaviour. He or she is expected to marry someone within their particular tribe and most Roma conform by marrying within their group. Even with respect to other Roma, permissible marriage choices may be restricted. This is a way of maintaining tribal and social purity. If a Gypsy male marries a gadjo, his community may eventually accept her, provided that she adopts the Romany way of life. But it is a worse violation of the pollution code (marimé) for a Roma female to marry a gadjo, because Roma women are the guarantors for the survival of the population. In the case of a mixed marriage, many tribes consider the children Roma only if the father is Roma. Next, Roma expect females to be virgins when they marry and to remain faithful to their husbands until death.