The age at which a male cat is neutered depends on a number of factors which are discussed here and stock answers are unhelpful.
However, veterinarians will provide you with a stock answer about when male cat neutering should take place giving the impression that the decision is settled and straightforward. I don’t think it is because the answer depends upon the circumstances and, in fact, theoretically, a male cat need never be neutered provided there was no chance that he could procreate and provided that the cat’s caretaker accepts the behaviour of an unneutered male cat.
The age at which a male cat is neutered is subject to various forces. On the one hand there is a desire to retain the natural body shape and confirmation of a male cat. Neutering him can alter that because of a lack of testosterone (how it affects a man). On the other hand there is a desire to stop male cats breeding because there are too many cats. Shelters, for example, will be eager to neuter a male cat as early as possible in an effort to combat the overpopulation of cats. In fact, many veterinarians and animal shelters are doing spaying and neutering on kittens as young as seven weeks of age (prepubertal gonadectomy). The North America veterinary associations support prepubertal gonadectomy. However, it may be too stressful for a kitten and it may trigger FIP (apologies but I have lost the reference). Note: neutered males can be fertile 4-8 weeks after the operation.
However, the usual or perhaps old-fashioned attitude is that the best time to neuter a male cat is when he is six or seven months of age. This is the time at which he is mature enough that his bone structure and his growth will not be affected by the neutering.
Today, I was at the veterinarian appointed by the rescue organisation which provided me with Gabriel (my cat) as a foster cat and the chief veterinarian there almost demanded that Gabriel was neutered there and then. He was booked in for a neuter but I wished to change it to a vaccination because I felt he was too young to be neutered. I argued my case successfully because he’s barely 4 months of age and I am keen to retain his physical appearance as a male cat as much as possible. In fact, I lean towards seven months of age for neutering in order to maximise the possibility of my cat retaining typical male body confirmation.
If the cat’s owner is responsible and ensures that his male cat does not have the opportunity to mate then I see no reason why a veterinarian cannot accept a request to neuter at six months of age if the owners so desires. The veterinarian does not have the right to dictate the time of neutering provided the owner complies with the contract between him and the rescue organisation. As it happens the contract that I have is defective because the time before which neutering is stated to take place has been left blank. However, the pamphlet provided by organisation states that it should take place between four and six months of age. As stated, I prefer the six months end of that timeframe.
Apparently, many vets feel that early neutering does not have any detrimental effect upon the male cat in terms of the way he appears but it is said that the main differences seen with early neutering include “slightly taller size due to delayed bone growth plate closure and the inability to extrude the penis” 1. Also if a boy cat is fixed before six months of age, or more accurately before the development of secondary sexual characteristics, “his penis may remain small”.
The veterinarian who I spoke with (in fact I argued with her) stated that in Britain the age at which a male cat is neutered has been revised downwards from six to four months. I asked why this had happened. She said that the younger cat is more able to deal with the operation such as issues regarding bleeding (the younger cat can recover better from the operation). In short, she was stating that the benefits of neutering at the younger end of the timeframe outweigh the detriments of doing it at that age. She did not discuss the potential detriments of early neutering.
As can be seen, however, there are benefits and detriments and neutering is weighing up these factors to find the best answer. The decision depends upon the specific circumstances. There is no one stock answer in my opinion.
A good book that I have on veterinary matters says that early neutering does not appear to increase any incidences of urinary tract problems. The urethral diameter appears remain the same. Studies indicate no long-term behavioural effects from early neutering. In contrast, neutering an older male cat may leave his sex drive unaltered although it is uncommon1.
Another excellent book I have, The Welfare of Cats, states that at one time there was concern among the experts that early neutering may cause stunting of normal growth patterns. Although there was little hard data to support this concern. However, the book does say that future, long-term follow-up studies may present to us issues hitherto unforeseen which arise out of very early neutering of male cats.
Of course, it all depends upon the level of concern by the cat’s caretaker. Sadly, in many cases early neutering is preferable when bearing in mind the habit of some cat owners to be indecisive about sterilising their cat until after a cat breeds and produces a litter. A small percentage of people believe that cats should be allowed to have a litter before be neutered/spayed but this simple desire is a major reason why there are so many unwanted cats.
My personal feeling is that neutering at 6 or 7 months is preferable because it pays more respect to the integrity of the male cat whereas pre-puberty neutering focuses heavily on preventing the bad habits of people (letting their cat breed) taking effect while overlooking possible health and development consequence affecting the cat. Early male cat neutering is human-orientated.