Islam is the national religion. The vast majority of Iranians are Muslims of the Twelver, Shīʿite branch, which is the official state religion. The Kurds and Turkmen are predominantly Sunni Muslims, but Iran’s Arabs are both Sunni and Shīʿite. Small communities of Christians, Jews, and Zoroastrians are also found throughout the country.
Shīʿism
The two cornerstones of Iranian Shīʿism are the promise of the return of the 12th imam—Mahdī, and the veneration of his martyred forebears. In the absence of the Imam in modern Iran a strong Shīʿite clergy has been developed. The Shīʿite clergy have been the predominant political and social force in Iran since the 1979 revolution.
There is no concept of ordination in Islam. Hence, the role of clergy is played by scholars, the ʿulamāʾ. To become a member of the Shīʿite ulama, one need only attend a theological school, or madrasah. The main course of study in such an institution is Islamic jurisprudence (fiqh). In Iran such a clergyman is generally called a mullah/ākhūnd/rūḥānī.
A mullah can study and gain the higher status of mujtahid (a degree similar to PH in Western education). Now, he/she will be called an “ayatollah”, the sign of God. He/she has acquired the authority to practice independent reasoning in legal-religious judgment (ijtihād). If an Ayatollah (mujtahid) has a substantial following among the Shīʿite community he rises to the level of one who is worthy of being a marjaʿ-e taqlīd (model of emulation), the highest level of excellence in Shīʿism.
There is no real religious hierarchy or infrastructure within Shīʿism, and scholars often hold independent and varied views on political, social, and religious issues. Every believer, in order to follow the authentic Islam, should follow the teachings of his or her chosen marjaʿ-e taqlīd. This has naturally increased the power of the ulama in Shia world.
Religious minorities
Christians, Jews, and Zoroastrians are the most significant religious minorities in Iran. They have their representatives in Iran’s majlis (parliament). Christians are the biggest group of these, Orthodox Armenians constituting the bulk. The Assyrians are Nestorian, Protestant, and Roman Catholic, as are a few converts from other ethnic groups. Jews live in Hamedan, Isfahan and Tehran in general. And the Zoroastrians are largely concentrated in Yazd in central Iran, Kermān in the southeast, and Tehrān.
Christians, Jews, and Zoroastrians are recognized in the constitution of 1979 as official minorities. Other beliefs like the Bahāʾīsm are considered as political factions forged by the colonial UK in 19th century and are illegal.
The new sciences started mostly from second quarter of 20th century in Iran. In 1960s, Shah enforced a land reform and emphasized industrialization which involved the importation of petroleum technology and the training of Iranian technicians abroad, but it did not improve Iran's indigenous technology.
After 1979, the Islamic Republic tried to enhance the higher education by reinforcing the existing governmental universities, and establishing a new system which is called “Islamic Open University”. This later one is run as a foundation and the students should pay for the courses they study.
There are a plenty of scientific institutions in Iran which are scattered all over the country. You can some down here as the samples :
International Scientific Research Institute, founded in 1955.
Iranian Mathematical Society
Iranian Society of Microbiology
Animal Husbandry Research Institute
Institute Pasteur.
One can find at least one university in each town in Iran.
Iran has also suffered a "brain drain" as the social and economic problems have escalated within the last 40 years.
Traditionally, the family and tribal system is very strong in Iran. This has affected the different economic, social or cultural plans put by the government.
There are powerful Social welfare programs which include workers' compensation, disability benefits, maternity allowances, retirement benefits, death benefits, and family and marriage allowances. These programs cover all employed persons between the ages of 18 and 65 who reside in this country. There is a special pension system in force for public employees. Old age benefits are available at age 65 for men and age 60 for women. Seasonal workers are covered for medical services during the working season. Employed persons in urban areas are covered by workers' compensation. Family allowances are available for working families with limited means.
Gender segregation is enforced in the public places, according to the Islamic law.
