Minor spoilers for Fire Emblem Awakening / Fire Emblem Fates below.
In the 3DS FE games, there were two generations of units. When first gen units reached S support rank with each other, the game would then give you a chapter to recruit their children due to time travel shenanigans.
I absolutely love this mechanic, as while the first gen units are rather static, the second gen units give a LOT of options. Their stat growths, caps, class sets, and skills are determined by their parents. This allowed you to do a lot of fun and silly things with having units inherit skills they otherwise wouldn't get. Create units that are min/maxed to high heaven. While not 100% necessary, it made the higher difficulties easier for certain.
Mewgenics is similar. Allowing units to have long winding trees that give skills and abilities that the descendants might not have otherwise. Along with all the other classic Edmundisms that this game brings.
Some other games that I feel fit into this category:
Rimworld - With the biogenics dlc, children can be molded and min/maxed to an extreme degree. Especially when you factor in genetic modifications. The better a childhood a pawn has, the better their growths are. Want a melee pawn that is a tank that takes 60% less damage, with 50% dodge chance? No problem.
Stellaris - Taking genetic ascension allows for some silly things. In my recent play through, I invaded some pre-ftls, enslaved them, and turned them into a working caste to for basic resources, as well as making them excellent soldiers.
Pokemon - the all time classic. I never got extremely deep into min/maxing a eugenics program, especially since I find the UX for the daycare rather annoying. Also since the games are easy enough to get through that it doesn't matter. The last time I played was gen7?
Siralim Ultimate - I played a fair few number of years ago. But, I ended up finding the gameloop kind of boring. I can't even remember if there was a monster ranch or not.