Why opposites attract

We have all heard the saying: Opposites attract. What most don’t know is that there is a biological and evolutionary impetus for that.

Opposites attract for more reasons you might imagine and for very good reasons in an evolutionary sense and the contraceptive pill might to contributing to an increase in immune disease and compromising immune function.

I am reading Secrets of your Cells, by Sondra Barrett, and she talks about the part that smell plays in bringing men and women together and the part that the contraceptive pill plays in interfering with the bodily and evolutionary wisdom of that process.

It is not that Barrett is making the connections I have, but reading what she says about the part that smell plays in bringing together a man and a woman who will offer their child the ‘best’ immune function in a biological sense, they seem to make a great deal of sense.

Research with mice showed that identical looking mice only mated with mice of a different genetic strain and the way they ‘knew’ the other was different was through smell. ‘Extensive research using an ‘electronic nose’ to discriminate the volatile components in mouse urine indicated that urine from different genetic strains showed different odour types, and this was reflected in mouse mating behaviour.’

A study done in 1995 by Swiss biologist Claus Wedekind, explored the theory that  HLA (cellular identity and markers which indicate the quality of immune responsiveness and also provide a distinguishing characteristic reaching beyond the invisible microscopic ‘self’) differences were connected to sexual attraction between men and women.

The study proved the research to be correct which, as Barrett says, makes sense from an evolutionary standpoint:

‘Remember that HLA ID markers indicate a range of immune abilities and immune responsiveness. If we mate with someone who has very different self markers from ours, our offspring will inherit a more diverse immune capability than if we pair up with someone having similar markers.’

The researchers found that a woman’s ability to discern these differences is lost when she takes birth control pills. When the research was repeated with women who had been on the pill for the initial study, men whose ‘smell’ had been attractive, were now found to be repulsive.

Which raises the question not only of how the contraceptive pill impacts the ability of a woman to choose a man who best ‘suits’ her on many levels, biological as well as psychological, but whether or not men and women are marrying when they are ‘unsuited’ at a biological or evolutionary level and this then plays a part in infertility.

Much of infertility today is unexplained, at least by science/medicine. Perhaps the explanation is as simple as the fact that nature will inhibit unsuitable procreation in ways we do not perceive.

And when children are born to couples who are a ‘poor’ biological and evolutionary match, are they also likely to have compromised immune function which predisposes them to allergies, reactions, diseases and sensitivities that those born to biologically ‘well-matched’ couples simply do not face.

I find it all fascinating and a reminder of how much we do not know and how everything in nature works for a reason.