@drak indeed, as you say, it's mostly "social pressure", not religion *itself* that does this. But it does happen in both Islamic and Jewish communities. OTH there are religions that it's not even possible to convert to (and where only marriage within the same religion is allowed) - like for instance the 'Parsi' in India (who have an essentially Zoroastrian religion)

@drak indeed, as you say, it's mostly "social pressure", not religion *itself* that does this. But it does happen in both Islamic and Jewish communities. OTH there are religions that it's not even possible to convert to (and where only marriage within the same religion is allowed) - like for instance the 'Parsi' in India (who have an essentially Zoroastrian religion)