Neutered male cat wants to mate with a spayed female in the same household. Why?

A cat owner on the Reddit.com website finds it difficult to understand what their male cat is doing to their female cat. They are both sterilised. The male cat is neutered, and the female cat is spayed. Therefore, the female cat doesn't come into heat. Why is the male cat pestering the female for sex?!

Neutered male cat wants to mate with spayed female. Image: u/Ok_Reference2122 on Reddit

The owner of the cats asks: "What is my cat doing to my other cat??? He will do these little chirps and follow her around mounting her like this but why? They are both fixed so he can’t be in heat."

My answer on Reddit was: 

"Neutered male cats might still desire to have sex with a spayed female cat. They may also desire to have sex with their owner's arm! The drive to mate is still there despite being neutered and the removal of testosterone. It's in their DNA. So being fixed does not stop this but it depends upon the individual cat. The little chirps he makes is a sign of excitement before mating."

The fact of the matter is that male cats even after being neutered and therefore even after the stopping of the production of testosterone, can still have a drive to mate with a female even when that cat is herself neutered.

And sometimes male cats have sex with their owner's arm or perhaps a leg or some other similar object. We see this quite a lot with dogs as well.

RELATED: Reason why some dogs try to mate with your leg.

Clearly, the drive by a male cat or dog to mate with a female is in their DNA and they will try and do it even if it is impractical. It becomes instinctive and illogical sometimes because they want to have sex with your arm.

It's just this internal drive and a lack of testosterone doesn't stop it in some individuals. I think this is very much about individuals and how they personally react to being neutered.

I speak from first-hand experience by the way because my cat has sex with my arm every day! I let him do it because it pleases him. There is a duty on all cat owners to please the domestic cat and it doesn't do me any harm so why stop it!?

For most dogs, the environment is sterile in terms of opportunities to mate with females. Forgive the pun. There is no opportunity and therefore they dive for the nearest object which is a substitute such as their owner's leg or the leg of an armchair or something like that.

It's all normal and dogs and cats should not be criticised for this behaviour. It's just that humans put them in a world where this kind of 'strange' (to humans) behaviour happens. From the dog or cat's perspective it is not strange but entirely normal.