I think I have always been a pretty sexy guy. When I was in my 20s I had three girlfriends at the same time, and I certainly kept them all satisfied. When I was in my late 30s I got married, and my wife and I have been real happy. However, I will confess to you, doc, that I do still have a girlfriend in Portland. I fit her in about once a week when I can just get there and back in an evening. What is making me fret is this: Recently, there have been one or two occasions when I have arrived at her place, and have been too tired to make love to her.

She is surprised by this, because in the 'old days' I would always have sex with her twice for the night. I cannot do this now.

As for my wife, she seems quite happy with our 'love life'. But we only have sex three times for the week now. At one time, we used to have sexual intercourse almost every day.

So, am I 'losing it', doc? I have also noticed that I am now a little overweight, at around 210 pounds.

A. Well, being overweight can affect a man's virility, so you should certainly slim down.

Overwork and excessive travelling can also diminish a guy's 'performance'.

However, you are telling me that currently you are having sex around three to four times for the week. I must inform you that this is WAY above average for your age (56)!

Scientists have found that the ordinary guy of 56 will only have about one sexual climax per week. So you are 'scoring' far higher than that.

You do not need a 'tonic' or any medication. But maybe you should take life a little easier now - and perhaps confine your sexual efforts to your wife, rather than driving off to 'fit in' this lady in Portland.

A. Yes, there is. Oral sex can transmit STDs - as can any type of sexual activity between two people.

I am not sure whether you mean that you gave this younger guy oral sex (that is, fellatio), or that HE gave YOU the oral sex (that is, cunnilingus). Or maybe both activities took place.

Anyway, either type of oral activity can transmit gonorrhoea and chlamydia - and other 'bugs' as well. So you should see a doc for a brief check-up and some 'swabs' - that is, tests which are sent to the lab. Don't fret: if you have acquired something from this man it can almost certainly be cured.

A. As a general rule, a guy of 46 will have a perfectly good sperm count. Many men become fathers at that age - or even a good deal older.

However, the extra factor in this man's case is that he has had some sort of accident to his genital area, followed by surgery for a 'ruptured urethra'. The urethra is the tube which runs from the bladder to the tip of the penis. It is quite often damaged by a severe blow to the underside of the male body, for instance, a powerful kick just behind the scrotum.

That damage may indeed involve a 'rupture' - which means that the tube bursts open.

Usually, a good surgeon can repair the rupture.

As to the 'railroad operation', the only 'railroad' surgery that I know of is a procedure which is carried out on the male's prostate gland. So I think you should just check with your guy whether he has had any prostate surgery.

Because of the fact that he has taken an operation in an intimate area of his body, you do need to ask him whether he is potent - in other words, whether he gets erections which are good enough to penetrate the vagina. Also, I feel you could ask him whether he would be willing to take a sperm count test. This is a simple and inexpensive procedure, and the results could reassure both of you. Good luck.

A. Sorry to hear about this. A lot of people find that when they try to settle down to sleep, the mind keeps 'chasing around' - thinking about all the worries of the day, and also about the future.

Very often, that type of excessive brain activity is associated with DEPRESSION. It can also sometimes be linked with 'bipolar disorder', which is often known as 'manic depression'.

I am not saying that you definitely have either of these conditions, but I do think you must have a good, long chat with a doc this week, to try to find out what is going on in your brain. I wish you well.