Robin williams was/is a psychiatrist who wrote 'Families and How to Survive them' with John Cleese,or vice versa.
As part of his introduction for groups of would-be psychiatrists,he tells them-at this point they do not know each other-to wander around the other people in the group without talking .
After a while they stop,and he asks them to name people they feel they could spend the rest of their lives with-I suppose within the context of the excercise.These people then go off and talk about themselves to each other to find similarities and differences in who they are,and who their families are.
He has carried out this excercise often.He says that invariably people in the groups with similar family backgrounds choose each other,and also says that there are individuals who choose no-one,and these people are orphans.
I suppose different things can be extrapolated.
My take on this is that genes manifest themselves in some way in the macro world of human beings,and at some level the human organism can recognise these manifestations.And also that the human behaviour can be manifestations of genetic organisation.And further,that human behaviours,to a greater or lesser extent,are an expression of stable genetic organisation,and are therefore an instrument for genetic organisation.

I said to my wife 6 months ago that I thought I had borderline Aspergers Syndrome.She thought,even for me,that was going a bit far.About a month ago,I was listening to BBC radio 4,and someone was saying that men were slightly autistic because survival in the good old days required the regimentation of all sorts of information and the checking of stuff all the time.Before we evolved into consciousness,instinct took care of that,and natural selection made sure our instincts were developed,and the genepool refurbished.I had a conversation with a friend about 30 years ago,in which he gloomily concluded that we were just chemical reactions.He was well-educated.I was in the middle of a love-affair with a philosophy of living,reading,among others,Carlos Castenada,bits and pieces of the Sufis,Taosim,Zen Buddhism,western psychiatry and mysticism.I was actually going to pieces.But at the time this statement was ok,because what are these chemicals anyway?What are their origins?And how have they come together to produce complex,coherent,functioning,responsive....organisms?It's as a miraculous,though unappreciated,explanation as any other.On the same tack,then as now,our existence can be,and is,defined within the context of carrying genes and behaviour that optimises the perpetuation of the gene pool,both species-wise and family-wise,couched in social systems,where we aquire identity and behaviour.This description has vaguely nihilistic undercurrents,but there is a converse.If you have ever gone into a new situation,whether social,work,or whatever,and you have no information or behaviour,it can be very intimidating,and aquiring working information and behaviour can be very painful.It seems to me that though our lives may be genetic constructs,it gives us the means to become familiar with the extraordinary phenomena of being alive and staying alive,and gives us a way to organise the material in our lives.The mistake is to think that this is the moon.