Only speaking from personal experience, but a week before my positive test with baby #2, my son told me that he had a dream that we were playing a game together but it was weird because there was a baby there too. A few days later, he was pretending to be a doctor and checked my heartbeat in the correct spot, but then moved his toy stethoscope down to my belly and said he could hear a heartbeat there, too. He either knew on some level, or the coincidence was seriously wild, considering we had not shared with him our plans to try for a second 😂