The first point to make is that we are discussing neutered male cats and spayed female cats. That has to be a basic criteria in this discussion. There’s no point comparing unsterilised male cats against spayed female cats for instance. It is just not a comparison that makes sense.
I can answer the second part of the question in the title from a study on the gender differences in the social behaviour of neutered full-time indoor domestic cats. It’s published on the Applied Animal Behaviour Science webpage and it was published in 1999. The scientists observed cats in 60 households. There were either two male cats, two female cats or a male and female cat in these households. They were aged between six months and 8 years. They concluded that “females were never observed to allorub other females. The male/male households did spend more time in close proximity.”
So, the males are more friendly towards other males whereas the females did not rub against each other. When cats rub against each other it is a sign of friendship as you might imagine. They also said that when cats live together longer there is less aggression which is common sense and completely foreseeable.
One veterinary website says that male cats tend to be more affectionate with humans as well, whereas females can be more standoffish. Another website says that male cats are more affectionate towards humans than females but they may be copying the other website!
PDSA which is a very big animal hospital network in the UK say that there might be some truth in the fact that females are bossier than males and males are more laid-back than females. However, they make the valuable point – and a point that I would make as well – that this is about individual cats and their own personalities.
Perhaps the biggest factor in answering the question is whether an individual cat is more affectionate than another cat. Their gender would be secondary to that question. They do not agree that male cats are more affectionate towards humans than females per se but state that some cats are more independent than others and some are happier with humans than others.
I could not find a research project on whether male cats are more affectionate towards humans than female cats. It’s all very well reading websites by amateurs on these sorts of topics but very often they do their research online and the whole process becomes very incestuous, each website copying the other.
Anecdotally, it is often said that male cats are more affectionate but this is not backed up by hard science. And neither is it backed up with my personal experience.
There may be an issue of confidence versus timidity in this discussion. For example, on the Reddit.com website one commenter said that they found an entire family of cats and the mum and kittens stayed in the bushes while the male cat walked out and allowed the person to pet them. They said that the male cat became friendly whereas the female cat remained cautious. This is a fundamental trend. Once again there will be variables between individuals.
But if a cat is more confident, they will accept being approached or approach a human themselves and in doing so they will be perceived as being more friendly. Friendliness accompanies confidence in the eyes of people. That might not be fair because sometimes shy cats can be incredibly friendly if you can tease out that aspect of their character.
One person commented by saying that female cats have a higher responsibility in giving birth to young and raising them whereas males don’t have this responsibility except for mating with females. The female’s added responsibility might make them more serious in nature than males. This may be perceived as a lack of friendliness and females. That’s very anecdotal and I am unsure of its veracity.
Conclusion: Anecdotally, yes, but there are many variables which make a conclusion unwise.
Below are some pages on feline affection.
Please search using the search box at the top of the site. You are bound to find what you are looking for.