LogFAQs > #986207632

MC_BatCommander posted...

Generational knowledge I assume, Vegeta and Goku knew how to fast track them now that they know it well

Goku was dead and Vegeta was focused exclusively on his and Trunks' training, he didn't even know Trunks could go Super Saiyan until he saw it and at that point Trunks had apparently been doing it for a while. Nobody was training Goten except Chi-Chi, and Goten's transformation happened accidentally.

Also part of Super Saiyan is that you need to experience a great personal loss or crisis, on par with seeing your best friend blown up or your mentor murdered by cyborgs. Trunks and Goten grew up in a time of peace and were fairly pampered.