That's a good read, and it may be 100% true, but it screams for some fact checking.
Some warning signs: the author isn't named, it has lots of figures but no sources cited, and has been circulating around the internet for years.
(The first article MR2 posted does list sources. The second article is about psychological differences and makes no mention of inbreeding, marrying cousins or genetic differences.)
For example, take this --
"According to the BBC, this Pakistani, Muslim-inspired inbreeding is thought to explain the probability that a British Pakistani family is more than 13 times as likely to have children with recessive genetic disorders. While Pakistanis are responsible for three percent of the births in the UK, they account for 33% of children with genetic birth defects."
Could cultural mores concerning abortion be a factor in the high rate of genetic birth defects among Pakistanis in Britain (assuming those figures are correct)?
Consider this - If you compare birth defects between the U.S. and France, you might conclude that the French are genetically superior. After all, France has 39.7 birth defects per 1000 live births while the U.S. has 47.8)
However, in France 96% of fetuses that have tested positive for Down Syndrome are aborted. In the U.S., around 67% that have tested positive are aborted. One might assume that fetuses that test positive for other birth defects are also aborted at a higher rate in France. I don't know how this willingness to abort changes France's overall birth defect rate, but it has some effect.
(I have no idea about how Pakistanis in the U.K. feel about abortions, and maybe abortions have no effect on those figures, but I throw that out there to show that figures without context can be misleading.)
Sources:
http://www.neonatology.org/pdf/MODBD...iveSummary.pdf
http://www.nationalreview.com/human-...-coming-france
http://onlinelibrary.wiley.com/doi/1...4F14F25.f02t01