I believe it will not effected to the growth of the cats. However, some vet don't want to neuter the cats below 5 months as some of the cats testicles is not very visible and due to their expertise.

However, some people choose to wait until they can see the sign of male character (broad face etc) to develop before choose to neuter, this is quite risky, because when they start to have the 'maleness' habits..is quite hard to overcome it even after neuter.