Jamie Lynn Spears knows the gender of the baby she's carrying -- and now she's telling the world. The tween queen will have a little girl right at the onset of summer -- her due date is June 29th, according to Life and Style magazine. A family friend says, "[Jamie Lynn's mom] Lynne said Jamie Lynn made a list of all the girl family names on both sides of the family and is trying to incorporate one of them as the middle name. Lynne's flattered to hear her name is being considered."