Five sets of prospective parents—at least two sets too many—experience pregnancy and childbirth in this adaptation of the famous self-help book. Director Kirk Jones can’t wrangle the mismatched storylines into a cohesive whole, juggling plotlines that range from the romcom wackiness of reality TV star procreation to African adoption to the tragedy that befalls a young couple after a one-night stand. That’s not even including the pointless sidebar scenes in which Chris Rock leads a posse of stroller-pushing dads. Elizabeth Banks and Anna Kendrick offer up some funny and touching moments, but the stars with the highest celebrity wattage (Jennifer Lopez, Cameron Diaz) deliver the dimmest performances, flailing against weak sublots. It’s admirable that Jones wanted to show the spectrum of pregnancy experiences, but his approach stretches the material too thin.