From Essential Hacks (http://www.simania.nl/sdls/eh/sdls-eh.htm):

The "Gay marriage hack"

In-house and same-sex marriages; other-sex and child move-ins; children can tell adult visitors to leave. Children will move out without taking a single parent with them; the last child in the house takes the budget and any remaining pets. (An extra dialog string was added for this, in all languages except the five Asian ones; they still have the old parent-moving-out message.) Move-ins and marriages (even in-house) can't take place while there's a baby in the house.
Files: GameData\Global\PersonGlobals.iff, GameData\Objects\SocialInteractions.iff
Last uploaded: 03-01-2005
Version: The Sims