We just went through this in the past 10 days. The folks here generally concurred on their opinion and, I must say, things have worked out well. We introduced an 8 week old female kitten (Sassy) to our 1 y.o. neutered male (Striker). He was unsure at first, then became outwardly aggressive toward the kitten. We separated as suggested and heavily supervised togetherness time. As my wife is a housewife/mother, the cats were able to have more association time, with her only intervening when it seemed Sassy was in danger of being hurt. We kept them separated overnight (to keep peace in the house).
It's been a little over a week and they get along very well. We've quit separating them since Striker seems to be assuming the role of "big brother/parent". They still chase each other and wrestle, but Striker now seems to know where to draw the line. Your results may vary, but the separation and supervised play time worked very well for us.
P.S. Soon I hope to have a few pics to show to all of you.