i try to increase some stats but for some reason the game crash when i try to inceminate the character .
If it gives you an error after crashing that says something like out of memory then it’s most likely that your machine needs more RAM. If your hardware is old or under-powered that could cause a bottleneck with many games. I’m no expert by any means, but in my experience that is what will cause you to “run out of memory.”
You could try to close down as many apps as possible to free up memory. Beyond that I don’t know what to do.
To add to what Silurian said, while I’m not 100% sure which type of Java this game uses (32bit or 64bit), I can say that Java runtime programs are typically assigned a certain amount of memory based on the program’s settings (and any command-line parameters given during launch). You could try looking into memory command-line parameters for Java 6 (the version this game uses) to see if you can assign it more available memory. Older versions of Minecraft used the same version of Java and could run into the same error, so you might find the correct parameters by looking at that.
If you don’t want to have to start from command line (or don’t know how), then you can create a shortcut for the .exe and then add the parameters to the ‘target’ section. Again, a tutorial for Minecraft will probably explain it better than I can.
Fertilizing an embryo creates a full data structure for the new character, so massive hyper-pregancies will quickly eat up the memory that the Java VM has available, and will slow down hourly processing pretty significantly, so it’s not necessarily something simple to play around with on older or slower machines.
Aside from a couple very outdated releases, the game doesn’t ship with Java - it’ll use whatever version of Java is installed on your machine. You’ll want to make sure you have a 64-bit operating system and that your default Java runtime is a 64-bit version - you can check this by opening a terminal window (cmd.exe in Windows, or the default Terminal app in MacOS or your Linux distribution) and running java --version or java -version. The output should mention something about 32-bit or 64-bit.
To do any further troubleshooting it’d be helpful to know what operating system and version you’re using, and how much actual RAM you have. On Windows, you can generally find this by opening File Explorer, right-clicking My Computer or This PC, and selecting Properties from the right-click menu; on a Mac, you can open the main menu and click About This Mac, or use the search tool to find System Information.