Corrected entry: When Phoebe goes to visit her birth mother in Montauk, her mom says "I wish someone would've been there to tell me how terrible it is to give up babies". The scene cuts to a shot of Phoebe holding the puppy, revealing a side view of a stand-in, not the actress playing her mom.
Corrected entry: When Phoebe is considering carrying her brother's babies, her mother gives her a puppy to look after. Chandler seems very comfortable with this puppy. However, in Series 7, when Phoebe brings a dog back to Monica's apartment, Chandler says he is terrified of dogs - especially puppies.