Book Review: Consanguinity in Context

The title told me that this was the monograph for which I
had been waiting. A further delight was that the author was a good friend and
colleague. By the way, there are no conflicts of interest (!); Alan Bittles advised
my colleagues and me as we planned studies in consanguineous families in the Trent
region in the UK during the 1990s and, more recently, in Oman. So, there was extra
confidence due to this book's reputable provenance.

This monograph is desperately
needed. Western societies, who often chose consanguineous marriage in the past,
have grown to fear it and to denigrate communities where it is commonly
practiced. Criticisms of consanguineous marriage come from sources expected to
be objective, but often failing in this respect. Healthcare workers and
laboratory scientists who have investigated disabilities in selected high-risk families
have been known to make comparisons without appropriate control subjects. Sometimes,
selective arguments, for or against, come from within the communities who often
choose cousin marriages (reported in BioNews 573).

The usual culprits then join the chorus. For example,
immoderate and ill-informed politicians or other seekers of publicity, who have
never attended real patients with disabilities nor looked at healthy control families
for comparisons of the burden of disease, may nevertheless add their own honest
concerns whilst using crooked thinking. Bittles' book is not just for those
in wealthy Western countries, geneticists, other scientists or healthcare
workers. It is also for professionals and families with genetic disorders throughout
the world.

Despite the unassuming title, this book is packed with
carefully collated information, covering all aspects of consanguineous marriage.
This includes genetics, culture, religion, legislation, demography,
socioeconomics and the relationship to many conditions that occur more often in
some marriages between close relatives. The compilation is exhaustive, fascinating
and rigorously discussed. Like all good scientists, Bittles does not select
data to augment his particular view; he gives all the facts, covering the
historical, social, geographical and scientific framework of consanguinity. He
also includes many gems, such as Francis Galton's wicked, non-politically correct,
comment to Darwin's son, George, who had published one of the first studies of
the limited adverse effects of consanguinity. You will now need to read the
book to find out what Francis said to his first cousin, once removed!

OK there's the hyperbole. Does this monograph fulfil
expectations? My answer is like that of the character Meg Ryan played in the
restaurant scene of 'When Harry met Sally': 'Yes, yes, yes, yes...Yes!'.

Every chapter starts with a clear introduction and ends with
a commentary that summarises the information available and all key issues. The
first chapter covers 'Consanguineous marriage, past and present' and the last 'Consanguinity
in context'. The wealth of information in between discusses a range of topics,
with the first third dealing with subjects such as religious attitudes and
rulings, historic scientific/medical debates and population genetics. Bittles
then delves into the influence of consanguinity on reproductive behaviour,
early life morbidity and disease in adults. In the final third of this
comprehensive book incest, genetic screening, education and counselling are
tackled.

Bittles' discussion of genetic screening and counselling
made me appreciate how little data there is showing what happens if high-risk
affected families with an autosomal recessive disease are provided with
non-directive genetic counselling based on an accurate family tree. Gathering
this data will surely be better than a general, ill-informed clarion call that
cousin marriage be outlawed!

There is so much information here, but it is all relevant,
well-validated, significant and stimulating. The book is littered with
fascinating facts, such as that in China, Taiwan, Korea and the Philippines,
legislation bans first cousin marriage, although China distinguishes between marriages
involving the daughter of a father's brother (banned) and marriages involving the
daughter of a mother's brother (acceptable)!

In the penultimate
chapter there is a thoughtful discussion of when consanguinity can be
beneficial to human health, the role of epigenetics and the influence of
consanguinity on donor matching for organ transplantation. As I read this chapter, I realised that only
if we learn the lessons implicit in Bittles' amazingly comprehensive, and
yet readable tome, will the opportunities for good 'blue skies' research into
customary cousin marriage be fully realised. Put simply, this book is exactly
what is needed to clarify discussions and debates about consanguinity. It
deserves to be influential in scientific, political and religious thinking. We
should applaud the single author of a major opus by giving his data the
attention it deserves.

Buy Consanguinity in Context from Amazon UK.