In The Sims 4, using the cheat “cas.fulleditmode” allows players to fully edit their Sims in CAS. Unfortunately, this cheat is bugged at this time, causing Parents & Children to be automatically set to “Siblings”. There are many users reporting this issue, so avoid using the cheat until it is fixed.
For now, use the “testingcheats true” then “Shift + Click Sims + Edit in CAS” cheat to edit your Sims clothing and hairstyles. This cheat is the same as “using the dresser”. Huge thanks to Everborn for tracking down the issue.
— Graham Nardone (@SimGuruGraham) September 6, 2014