Care and Feeding Photo illustration by Slate. Photos by Eliyahu Parypa/Getty Images Plus and ktsimage/Getty Images Plus.  Care and Feeding is Slate’s parenting advice column.  Have a question for Care and Feeding?  Submit it here . Dear Care and Feeding, My mother-in-law, “Pam,” has always been a bit of a conspiracy nut, but lately she’s gone off the deep end. And my husband is going right along with her. Pam thinks our 20-month-old was abducted by aliens and replaced with an identical copy of him that was created to observe human beings for the purpose of an eventual invasion. It’s gotten so bad that Pam is demanding we take him in for X-rays at the doctor’s so we can see the alien life form inside. And she’s forbidden him from coming over to her place and is refusing to visit us until we do. My husband thinks we should just do it to get her to shut up. I am not subjecting my toddler needlessly to X-rays for the purpose of proving his crackpot mother wrong!…