I agree with the other moms, that your kiddos can take baths together and it shouldn't be an issue. When one requests privacy you should of course allow them to bathe on their own. I have read that for kids around the age of 3 that seeing the opposite sex parent naked can cause some confusion and should be avoided, but its ok to see the same sex parent naked after age 3. I doubt that applies to siblings close in age. I have 2 daughters who bathe together and see me naked all the time, but my 4 yr old always kicks me out of the bathroom when she poops. I respect her wishes, but I think it's funny.