So, while watching DBZ (not super) I thought of something. Why can Gotenks go ssj3 but is never seen going super saiyan 2? Furthermore, how can Gotenks go SSJ3 at all if Goten and Trunks can only go SSJ? Am I missing something?
Daizenshuu #7 (Special Attack Index, pp. 124) states that Gotenks is able to go SSJ2. Fortunately I got a Japanese scan from a website, you can compare it with the translation.
[Read it from right to left]
- I covered the Gotenks' part with the red box. Those are the special attacks/moves he can perform.
- While in the blue box, it states "~SSJ2" and "~SSJ3" which means he can perform those too.
- You can visit here to look for translation for this page. FYI, do Crtl+F and type in "gotenks" in the search box on the top right corner to search for Gotenks.
You can briefly see SSJ2 Gotenks in both manga and anime. Gotenks never uses the form in combat, instead he bypasses it to ascend to SSJ3. (Source)
It is unclear that Hybrid Saiyans may become Super Saiyan faster than pure-blooded Saiyan or possess a naturally greater potential than their Saiyan parents. But, Gohan become Super Saiyan at the age of 11 (9 in manga). While Trunks and Goten were able to make the transformation to Super Saiyan at a far younger age than their fathers, at the age of 8 and 7 respectively. You can refer more from one of my answer about this topic here. If the statements above are true, it is likely that Hybrid Saiyans can achieve any form of SSJ faster than pure-blooded Saiyans.