First of all: I really liked the game. It has really great ideas and the animations are good.
Some comments: Put H (Hermaphrodite) for Futa instead of F, since F is also for Female.
Will traits affect something? If yes, put a description for them
The breeding selection is a bit janky when you only have 2 monsters. I couldn't select one of the monster without leaving.
It's not clear which breeding has animation and which hasn't, especially since pregnant sex is considered separedly, so you can't randomly test. I suggest that you put a similar screen to the breeding screen on the main menu telling you clearly which animation can be done (You select the giver on the left, it shows which female has an animation on the list to the right (either be not showing those without one or greying the name)). When the game is complete, you can even change that into a gallery/sandbox.
Maybe add an item that renders the female infertile so that you can mess as much as you want in the breeding pen. (No need to add a line in the infos, it can be a another state of pregnancy)
An item allowing to rename your monster would be nice.
Other recommendation: attack increase should be additive, not multiplicative. At the start it's okay, but past a certain point, you can one shot enemy of your level with that. Example: At level 1, a punch with 20 PA deal 30-10PD= 20 Dmg; at level 10, assuming your PA increase by 3 and the enemy PD increase by 2 points each level: 50PA deal 75-30=45; at level 20 it's 80PA deal 120-50=70Dmg and it goes on. And I don't even talk about sunder. So I would suggest to only use additive or multiplicative in damage calculation but not both at the same time.
Another recommendation: Exp sharing. Grinding for your monsters is really annoying and slow. My 2 possible suggestions: 1) all your monsters not in combat (or the first 5 in the list) get "enemy level" minus "their level" EXP if the enemy level is higher than them; 2) Releasing a monster give super candy but it only work up to your highest monster level minus five
I don't know if it can easily be done, but adding a way to freely reorganize your monsters would be nice (but it's already possible by using set as leader, so skip that if it's too difficult)
I also don't know if it's hard, but a way of storing your monster would be nice. Even better if it is 2 storages: 1 remove from battle but not from breeding, the second removes from battle and breeding
Small bug I had: after sleeping at the house, while typing the name of a new monster, the dialogue asking if I wanted to rest popped up while pressing H
Another bug: if you selected your character in the last breeding, in the next breeding she is already selected. But if your directly breed after selecting a giver, the game softlock at the end of the animation
Bug: The Mimosa Quest (Horny Infection) can't be completed. I can't give the cure to the innkeeper and the receptionist. It may have happened because I interacted multiple times with NPCs and the fountain
Bug: You can increase penis/balls size on female; and breast size on male with no change at all
Small mistake: a monster can be born/encountered without any attack skill, only debuff
The game is quite early in development, but I really like what you have done so far. I will follow how the game progress