One can guess the gender of new kittens by the shape, size, and distance from the anus of their reproductive parts. Moreover, male cats have testicles as well.
Like all other male animals, male cats have a heavy and tall build. They tend to weigh more and appear taller than female felines.
A male feline would need around nine months to more than a year to gain sexual maturity. A female kitten can attain sexual maturity at only seven months.
The average life span of cats, irrespective of gender, is 11 to 15 years. Life expectancy has more to do with breed than with gender.
There is no proof of one particular gender being healthier than the other. The overall health gets better if the cat is spayed.