(Note: This post contains minor spoilers for Fire Emblem: Awakening.)
Fire Emblem: Awakening is my favorite example of accidental eugenics in video games. Fire Emblem is a series of turn-based strategy games set in a pseudo-medieval fantasy setting with magic and dragons. One of the aspects that makes Awakening unique is that not only can the characters become romantically involved with one another, they can also have children who will travel through time from the future as fully-grown adults to help your cause. These children’s maximum potential stats depend on who their parents are. In addition, they inherit a Skill from each of their parents (including skills that they should otherwise be unable to have) and have access to any class that either of their parents has access to.
The romance and child mechanics can have a massive impact on how players approach the game. In order for characters to engage in romantic relationships, they need to fight together on the battlefield by either having them occupy adjacent tiles from another or using the game’s “pair up” mechanic to effectively have them act as a single unit. In addition, characters with certain classes can gain relationship levels with friendly units by interacting with them, like healers or dancers. As a result, there are effectively three ways to approach the mechanic. The first is to simply play the game with no attempt at intervening in the characters’ romantic destinies, simply allowing relationships to flourish naturally and seeing how the story evolves from there. However, players can also choose to take the characters’ romantic destinies into their hands. Some players will intentionally pair units together in combat despite the tactical risks involved simply because they think the characters make a cute couple. Other players will use this mechanic to create an army of Übermensch super soldiers.
Awakening provides a lot of options to customize the game’s difficulty level, meaning the game can be either a casual and easy-going experience or an absolute nightmare that forces you to use every strategic option available to you just so you can have a chance to win.