Oh. Do not let big words (engine, framework, ...) frighten you. These words do not necessarily mean you have to go into "think tank" mode before writing any line of code. BillBellochek is right. In a first time, a simple version can be done without any need of mesh or modeling. Just the nutrition and transmission systems. Feasibility is good, considering the impressive work modders have published on this forum. for the mecanic, SexLab Arousal can be used to handle the growing "need" for fluid and a pregnancy mod can help for transmission (impregnation) and fluid tank.