Edited sentence: Certain ethno-religious groups practise endogamy to a relatively greater extent and this inevitably leads to a level of auto-segregation.Ethno-religious groups which have successfully resisted integration for the longest, for example the Romany gypsies of Europe, practise a higher level of endogamy.Exogamous cultures however, will naturally tend to integrate and merge with surrounding populations to a greater extent.Islam prescribes a limited form of endogamy, Muslim men can take wives from neighbouring non-muslim populations but Muslim women are normally forbidden to marry outside of the community