First-Born Syndrome

First-Born Syndrome, also called the First-Born Effect, is the name given to a persistent error in The Sims 2. This error affects how the game determines the genetics of newborn baby Sims. The error has never been officially patched out of the game, but there are a number of ways to mitigate or completely prevent it from occurring.

Background
In The Sims 2, when a pregnant Sim gives birth, the game pseudorandomly determines the new baby's (or babies') physical and personality traits (e.g. hair color, eye color, skin tone, personality points). However, a quirk of the game's genetics system is that the genetics sequence restarts from the same place every time The Sims 2 is loaded. In a situation where a player has a pair of Sims have multiple babies in different play sessions, the first baby born in each play session will have identical genetic traits as the couple's first-born child; this is known as First-Born Syndrome.

Fixes
The community has found or has developed several workarounds or solutions to First-Born Syndrome over time. However, the error is persistent in The Sims 2 and has never been corrected by any official patches, expansions, or stuff packs.

"Rolling the pacifier"
The first and most basic solution to First-Born Syndrome is for the player to "roll the pacifier." Rolling the pacifier is only necessary if the couple has already had at least one child, and only if the previous child/children was/were not born in the current play session (i.e. The Sims 2 has not been closed or restarted). To roll the pacifier, a player needs to enter into Create a Sim before a pregnant Sim gives birth, but in the same play session as the birth. Once in Create a Sim, the player can create a new Sim, and click a few times on the 'randomize' button (the button just above the name field, that looks like a pair of dice). Alternately, the player can create a male and a female Sim, then enter into Make a Child and click on the. Doing either of these things re-randomizes the game's genetics sequence during the current play session. The player does not need to keep the Sim(s) they've created in Create a Sim, and they can be safely canceled.

Modifications
There are a number of player-made mods that address First-Born Syndrome. Among the mods available for download are:


 * More Awesome Than You's FFS Lot Debugger mod, also known as "Batbox." Note that players will need to manually save the lot they're playing before randomizing genetics.
 * Sims2RPC mod by LazyDutchess on Mod The Sims (also available via LazyDutchess's Tumblr)

As with all other mods, these are installed and used at the player's own risk. Players should make sure that any mods they download do not conflict with any other mods they've already added.