That's men for you: We have entered the season when the chatting up of women by men and men by women reaches manic proportions. But though it may all seem like madness, be assured that old Mother Nature is working away craftily in the background.
Testosterone is the hormone that makes lads lads: boost the level of testosterone in the bloodstream and we start sniffing around for a mate, if only for the night.
Lower the testosterone level and we are more likely to behave ourselves.
Mother Nature, the theory of evolution tells us, is primarily interested in ensuring that we pass on our genes and so perpetuate the species. In other words, Mother Nature is interested in promoting the mating game.
Chaps who are footloose and fancy free and who want to stay that way are, of course, favourite targets of hers.
For instance, a piece of research conducted at Harvard University found that testosterone levels are higher in single than in married men.
They found this out by measuring testosterone in the saliva of men who were married, single or married with children.
The single men maintained the highest testosterone levels throughout the day. The lowest were in men who were married with children.
Hence, the single men have testosterone levels that send them off in search of mates, while the married men with children are more likely to stay at home. The researchers suggest that being with their wives and children causes the testosterone of married men to fall. One wonders if this explains the adulterous activities of some of those Jack the Lads who spend as little time as possible with their families?
When our testosteroned male goes off looking for a mate, sly old Mother Nature is at hand again.
A team at the University of Chicago paid male students to have their saliva tested at a laboratory.
A young, female research assistant "happened" to be in the lab. Naturally, the male students chatted to her. When their saliva was tested it transpired that chatting to her had boosted their levels of testosterone by up to one third.
The men with the highest testosterone increase were the ones who later said they found her particularly attractive. And here is the scary bit, guys: before she had seen the test results, the lab assistant was able to say, accurately, who these men were.
Transpose that experiment to the heated and intoxicated atmosphere of an office Christmas party and the results hardly bear thinking about.
Other research at the Institute of applied psychology in Lisbon, found that men who were trying for a baby with their partner had higher testosterone levels.
Their levels of testosterone peaked during periods of intense sexual activity.
Some experts believe that in these cases the man is responding to his partner's pheromones (chemical messengers) - without realising it, he is synchronising his testosterone level to that point in her cycle when she has the greatest chance of of conceiving.
Pheromones, by the way, are also thought to explain why women who live together tend to have their periods around the same time.
With all these chemicals flying around, how come people are not attracted, generally speaking, the blood relatives?
According to British psychologist Dr John Marsden, the answer lies in our sense of smell. it appears that variations in our immune systems change the way we smell to other people. Blood relatives with similar immune systems to our own smell differently to strangers with immune systems unlike ours - the difference helps to switch off the attraction to relatives.
By all these strategies old Mother Nature, who is by no means the butter-wouldn't-melt-in-her-mouth figure she is often made out to be, keeps us breeding and mixing genes.
So much for free will. When you get hitched up to your partner for life it has more to do with chemistry than you might imagine.
And when your partner tells you in the course of a blazing row: "I don't know what I saw in you," you can reply: "You're right. You don't."
Padraig O'Morain is a journalist and counsellor accredited by the Irish Association for Counselling and Psychotherapy.