At the moment, the only option for testicle numbers possible in-game are from none up to 4.
- I am uncertain if the character can obtain just 1, but the game supports describing it as singular.
- 2 testicles should be the default and is obtained normally with most ball growth scenes and via the character creation.
- 3 testicles can be obtained as through events or items:
- A rare consequence of being immobilized with oversized balls in a non-hostile area, the character is unable to shrink them with masturbation or otherwise, and possessing less than 10000 credits. If the character has breasts with the top row having less than 3 breasts, there is a 1/2 chance that the character will instead have 3 breasts for that top row (so either 3 breasts or 3 testicles), otherwise this change will be guaranteed if the character has no balls or less than 3 testicles.
- Ruskvel: 1/4 chance with a penis and less than 3 testicles.
- 4 testicles can be obtained via a destined character name during creation, or as an effect from a transformation item/event:
- Fuzzball Candy: Having 2 or 3 testicles when taking it--incredibly rare (1/20 chance) but higher chances with overdosing the candy within a 24-hour period, guaranteed on the next dose when 20 overdoses or more.
- Laquine Ears: Having 2 testicles and a penis during the major transformation. Higher chances the more penises the character has.
- Semen's Friend Candy: A potential result when taking two or more doses during the item-effect's time period, having 1 to 3 testicles with a ball diameter greater than 5".
- Treatment: 1/10 chance during the Bull variant on the 155th hour if the character has 1 to 3 testicles.
So technically there aren't "rows", just a number, but I hope this helps.