Evaluating the impact of motherhood on a woman’s career is complex. There are interrelated mechanisms resulting in conflicting results. The wage disparity for mothers is noted within the literature to range from 0 – 20 percent, with a similar spectrum of negative impact on career progression, when compared with fathers and childless men and women. In this research I summarize the predominant theory-based explanations for the motherhood penalty and review a sample of the research published from 1979 to August 2023. This study shows evidence that a wage penalty for motherhood continues to persist ranging from 14 percent to 32 percent. From the NLSY97 sample of working women (2004-2021), there is evidence of a wage boost for married and divorced mothers, women who choose to delay fertility may experience a wage boost, race and a woman’s level of grittiness have no significant impact on women’s wages, and human capital considerations continue to matter and may work to attenuate any wage penalty for motherhood.