This study explores possible implications of gender and parenting difficulty of the first-born child on parity progression among parents in Japan, a country with widespread daughter preference. Past research reveals that having a child of the less preferred gender is associated with a higher probability of a subsequent birth and a shorter birth interval if couples choose to have an additional child. Therefore, having a child of the less preferred gender (boy) may be associated with a higher probability of another birth and a shorter birth interval in Japan. But difficult parenting experience with the first-born is also known to affect fertility negatively. Boys are considered more difficult to raise than girls as they are more prone to illness and injuries, physically active, and require parental attention. Hence, parents of first-born sons may rather hesitate or postpone having another child. Using the Longitudinal Survey of Newborns in the 21st Century, a nationally representative longitudinal survey of children born in 2001 in Japan, this study explores these explanations. Results from discrete-time event history analysis to examine transition to a second birth among parents of first-born children surveyed reveal that gender of the first-born did not affect parity progression. Regardless of the gender, parents with difficult first-borns were less likely to have another child. Findings highlight the importance of continued policy efforts aimed at addressing parenting concerns and burden.