The welfare effect of an additional child cannot be stated simply and unequivocally

There is no single calculable welfare effect of an additional person. Rather, there are many different judgments, which may be negative or positive. The welfare effect depends upon the particular economic situation the child will be born into, which point in his life-cycle one refers to, whether he is expected to have a positive effect upon his particular sort of economy and society during and after his lifetime, and most of all, on the kind of welfare criterion used. Furthermore, no matter which welfare criterion is used, the welfare effect of an added individual summarized over time is especially sensitive to the particular assumptions made.