There was a decline in consanguineous marriage rates in Lebanon between 1950 and 1970, from an overall rate of ca. 30% down to 20%.[1]

There has been an increase in consanguineous marriage rates since 1983-84 when the overall rate was 25%[2] to the 2000s (2008?) when the overall rate was 35.5%[3].

Reportedly, there has also been an increase in the wearing of headscarves in this period, i.e. since the 1980s:

The wearing of headscarves has risen since the 1980s, even though Lebanon is generally more liberal than other Mideast countries and also has larger Christian and secular communities. Women who support Hezbollah, the Shiite militant group, wear headscarves generally and some wear the Iranian-style chador, which covers the hair and body but not the face or hands.[4]

__________

[1] Parental consanguinity and congenital heart malformations in a developing country

[2] Consanguineous Marriage and Reproduction in Beirut, Lebanon

[3] Consanguinity in Lebanon: prevalence, distribution and determinants

[4] A Look At The Wearing Of Veils Across The Muslim World, International Herald Tribune, Oct 31, 2006.

Iran is a nation composed of multiple ethnic groups and religions. Islam is by far the most important religion — something in the order of 98% of the population claim to be Muslims — and Shia Islam is the most important branch. The peoples of Iran include Persians, Azeris, Kurds, Lurs, Arabs, Baluchi, Turkmens, Armenians, Assyrians, Jews, and the Qashqai amongst others. Many of these groups now live in urban centers, but many are still rural-based agriculturalists while some remain nomadic herders.

The overall consanguinity rates reported for Iran are as follows: in 1977, 40%[1]; in 2001, 38.6%[2]; and in 2003, 58.2%[3]:

The overall consanguinity rates for Tehran were 25.1% in 1966[4] and 31.59% in 1991[5]; in rural areas the rates were 32.8% in 1966[4] and 46.86% in 1991[5]:

Given and Hirschman noted that in 1977, consanguineous marriage was higher among the younger cohort of women than amongst older women.[6] And in 2005-06, Akrami, et. al., found that the number of consanguineous marriages had increased across three generations of Tehranis[7] (my own chart based on their data):

It appears, therefore, that the overall consanguinity rates in Iran have been increasing since at least the 1940s or since the generation(s) that were married before 1948 as defined by Akrami, et. al.
__________

[1] Given. B, P., and Hirschman, C. (1994) Modernization and consanguineous marriage in Iran. Journal of Marriage and Family, 56, 820-834.

[2] Saadat, M., Ansari-Lari, M. and Farhud, D.D. (2004) Consanguineous marriage in Iran. Annals of Human Biology 31, 263-269.

[3] Saadat, M and Mohabbatkar, H. (2003) Inbreeding and its Relevance to Early and Pre-reproductive Mortality Rates in Iran, an Ecological Study. Iranian J Publ Health, Vol. 32, No. 2, pp.9-11.

[4] Behanm, D., & Amani, M. (1974). La Population de L’Iran. Paris: CICRED.

[5] Farhud, D.D., Mahmoudi, M., Kamali, M.S., Marzban, M., Andonian, L., and Saffart, R. (1991) Consanguinity in Iran. Iranian Journal of Public Health 20, 1-13.

[6] Aghajanian, A. (2001) Family and Family Change in Iran. (“Paper to be published as a chapter in Diversity in Families: A Global Perspective edited by Charles B. Hennon and Timothy H. Brubaker, Belmont, Ca: Wadsworth Publishing Company.”)

[7] Akrami, S.M.; Montazeri, V.; Shomali, S.R.; Heshmat, R.; and Larijani, B. (2009) Is There a Significant Trend in Prevalence of Consanguineous Marriage in Tehran? A Review of Three Generations. J Genet Counsel 18:82–86.