In a range of other countries - such as Bangladesh, Egypt, Indonesia, Kuwait and Jordan - publication of atheist or humanist views on religion are totally banned or strictly limited under laws prohibiting "blasphemy".
In many of these countries, and others like Malaysia, citizens have to register as adherents of a small number officially-recognized religions -- which normally include no more than Christianity and Judaism as well as Islam.
Atheists and humanists are thereby forced to lie to obtain their official documents without which it is impossible to go to university, receive medical treatment, travel abroad or drive.
In Europe, sub-Saharan Africa and Latin and North America, countries which identify themselves secular give privileges to or favor Christian churches in providing education and other public services, the IHEU said.
In Greece and Russia, the Orthodox Church is fiercely protected from criticism and is given pride of place on state occasions, while in Britain bishops of the Church of England have automatic seats in the upper house of parliament.
While freedom of religion and speech is protected in the United States, the report said, a social and political climate prevails "in which atheists and the non-religious are made to feel like lesser Americans, or non-Americans."
In at least seven U.S. states, constitutional provisions are in place that bar atheists from public office and one state, Arkansas, has a law that bars an atheist from testifying as a witness at a trial, the report said.