Op-Ed Contributor - Till Children Do Us Part - NYTimes.com
The answer is yes if the children are unplanned, if one of the partners is unwilling or ambivalent, or if people are forced to give up their jobs and lives to raise the baby. Which I suppose should all be filed under "duh."
Over the past two decades, however, many researchers have concluded that three’s a crowd when it comes to marital satisfaction. More than 25 separate studies have established that marital quality drops, often quite steeply, after the transition to parenthood. And forget the “empty nest” syndrome: when the children leave home, couples report an increase in marital happiness.
. . . most studies finding a large drop in marital quality after childbirth do not consider the very different routes that couples travel toward parenthood.
. . .
The Cowans found that the average drop in marital satisfaction was almost entirely accounted for by the couples who slid into being parents, disagreed over it or were ambivalent about it. Couples who planned or equally welcomed the conception were likely to maintain or even increase their marital satisfaction after the child was born.
Marital quality also tends to decline when parents backslide into more traditional gender roles. Once a child arrives, lack of paid parental leave often leads the wife to quit her job and the husband to work more. This produces discontent on both sides. The wife resents her husband’s lack of involvement in child care and housework. The husband resents his wife’s ingratitude for the long hours he works to support the family.