On the Sims 2, why do the relationships of resurrected people dissapear?

For example in Veronaville, Romeo's father and mother were resurrected. On the relationship panel they show as family, but they are not married. For some reason they don't like each other as much as they used to. (Well I don't know how much they used to like each other because they were dead when I got the game.)On the Sims 2, why do the relationships of resurrected people dissapear?
Because all ties end in death because the character doesn't exist. Call it a programming flaw. :) You could use such things as the inseminator to rectify those pesky little things though. Have fun!