Cat becoming less affectionate?

We've had Malachi since about late April. He was about 6 months old when we got him and his estimated date of birth places his birthday some time in October. He used to be very affectionate and would jump into your lap and crawl onto your chest for cuddles but has stopped doing that recently. He stopped jumping into my lap a couple months ago and hasn't cuddled with my father for a few weeks. Is this typical cat behavior or is something we're doing causing him to not be as affectionate?

Some cats get that way when they get older.

Is he neutered?