Does the age when you neuter a kitten affect the development of behavior problems? No, suggests a study published in a recent issue of the peer-reviewed Journal of Veterinary Behavior: Clinical Applications and Research.
The Winn Feline Foundation recently published a report on the study, finding no evidence that spay/neuter age in shelter cats increases the occurrence of undesirable behaviors including "inappropriate elimination, non-play-related aggression, fearful behavior, or destruction" during the 24 months after being adopted.
What did affect those behaviors, positively or otherwise, were owner and environmental factors such as "use of punishment by the owner, single cats, positive interaction with owner or family members, and so forth."
You can read the Winn report here; the article abstract can be read at the link below, where the full study can also be read by journal subscribers or it can be purchased.
Nathalie Porters, Hilde de Rooster, Katrien Verschueren, Ingeborgh Polis, Christel P.H. Moons, Development of behavior in adopted shelter kittens after gonadectomy performed at an early age or at a traditional age, Journal of Veterinary Behavior: Clinical Applications and Research, Volume 9, Issue 5, September–October 2014, Pages 196-206, ISSN 1558-7878, http://dx.doi.org/10.1016/j.jveb.2014.05.003.