Scientists from Canada and America (London school of Economics and political science, Western University, Canada) conducted a study and found that during the first two years after the child's birth parents have an incredible wave of happiness.
Emotional lift develops from birth and before his second birthday. Next feelings gradually stabilize.
Interestingly, the second child also causes positive emotions, which remain at the same level. The third child is often born spontaneously, so it is not always desirable. Then parents become in a very strange position, have mixed feelings.
In addition, scientists have proven that the parents are older, the longer it persists the period of absolute happiness of the parents. Most likely, this relationship is due to the large number of attempts to have a child among Mature and senior couples.