Is it true that letting babies cry in the morning can make their heart and lungs grow stronger and letting them at night can make them gassy?

It is not advisable to let a newborn cry over an extended period of time. Crying for too long may cause them to be more gas prone as there is an increased inhalation of air then usual. Babies cry as that is their only way of communicating to us. It is both normal when a baby cries when in need and when is just plain fussy. The website below will be able to give you a better picture. http://www.babycenter.com/404_is-it-true-that-crying-strengthens-a-babys-lungs_10323703.bc Hope this helps.