More than one woman over the years has called me spineless. At the time I was insulted but now it seems that being a spineless male has a distinct and most pleasant advantage.
The BBC reports that scientists believe men once had small spines on their genitalia along the lines of those found in chimpanzees, cats and mice.
A study published in Nature gave details of an analysis of the genomes of humans, chimpanzees and macaques which indicates that a DNA sequence thought to play a role in the production of these spines have been deleted in humans, but has been preserved in other primates.
The researchers at Stanford, Georgia and Pennsylvania State universities in the US wanted to trace evolutionary changes in human DNA.
They compared the human genome with those of the chimpanzee and macaque, and came up with 510 stretches of DNA that have been conserved in our primate relatives but deleted in humans. Nearly all them appear to play a regulatory role in the function of nearby genes.
Penile spines are barb-like structures found in many mammals. Their role remains under debate, and they may play different roles in different species.
They may increase stimulation for the male during mating. They might also play a part in inducing female ovulation in a small number of species, but there is evidence that they can cause damage to the female too. There is also the suggestion that they might have evolved to remove "mating plugs" - material that some male species deposit in the female genital tract to block other males' attempts to fertilise the same female.
The researchers believe the loss of these spines in humans may be related to changes in human courtship. The loss of spines, they say, would result in less sensitivity and longer copulation, and may be associated with stronger pair-bonding in humans and greater paternal care for human offspring.
Whether the theories about the function of penile spines are correct or not I am glad that they have been evolved away[ the not-wife of course is even happier!