I'm curious to hear what book recommendations you all might have for a 3 year old about pregnancy/labor and becoming a big brother. My little guy is happy and excited about the baby coming and is convinced it will be a sister. He has asked how the baby will get out and earlier today "took the baby" to "carry" it for me in his belly. :) So, he is into it so far and I thought after we find out the sex in a couple weeks I'd bring home a book for him...
For DD2 (who was 2 in June) we got "there's a house inside my mummy" which is more about how the baby is growing in me, and doesn't really go into how it got there or how it's getting out. She loves it and has definitely "gotten" that there's a baby in there.
For DD1 (who was 6 in April) we got "let's talk about where babies come from" which is recommended by the FPA (family planning association) and is a really good, detailed book which covers everything from puberty, through menstruation and sperm production, sex (which it explains with positive language and illustrates with cartoons of a couple under blankets (covered up) smiling and kissing one another - it's really sweet!) through pregnancy and birth and even covers adoption and same-sex relationships. She loves it.
Last summer (i.e. before we were expecting a baby) we checked out a book from the library because we liked the cover. It was called Too Small for Honey Cake. I ended up ordering it from Amazon because I adored the illustrations, but the story itself is cute too. It is told from the P.O.V. of Little Fox, who gets a little jealous when a new baby comes into the house. He gets jealous about having to share his old cradle and his father's attention, and gets annoyed that he has to be quiet when the baby is napping, etc. It's not a perfect story imo because Little Fox does say some pretty mean things about the baby, and acts out a little, but it's an honest look at a young child's emotions about sibling rivarly without judging or shaming them. Btw, there's no mom in the story, just a Daddy Fox... which was a little odd to me, but hey. It has a happy ending, naturally.
I think that book might come in handy to have on a shelf in case sibling rivalry rears its head (esp. with a three year old) but I wouldn't necessarily show the book to them FIRST while you were pregnant, i.e. putting the thought in their heads that the baby might be a problem. But if jealousy did happen in the first few days or weeks, it might be helpful to have on hand to help the kiddo process their emotions.
We have two Rachel Fuller books too, but DD really loves What Baby Needs by Dr. Sears. It's an attachment parenting style book, shows breastfeeding/cosleeping/babywearing etc. DD will listen to the story, but what she loves to do most is for us to ask her "where is the baby?" or the mommy or big sister or daddy, etc. on each page, so she can point to the appropriate person. She is starting to understand even at only 17 months!