This will result in stretched babies and sims, invisible babies, guys with breasts, floating hats or cut-off feet. There is another type of bad CC: Cloths and Accessory that are categorized for the wrong gender or age. Since those errors are mostly seen in packages and only a few that got converted into sims3packs, I think this part is covered. For this, Delphy wrote the Dashboard for packages and Clean Installer (aka Custard) for Sims3Packs (with custard you have to check every single sims3pack before you install). Some cause Blue lots, some slow your game down and some can even crash it.
There are a lot of CC out there, some in Sims3Packs, some are Packages.
