Previous studies indicate that the use of disability benefits is associated with reduced chances of having children. The current study aimed to identify the bidirectional nature of this association which has been overlooked in previous research. The longitudinal data used in this study were obtained from the Swedish national registers. It consists of 440,200 individuals born from 1968 to 1970 with a follow-up period extending up to 2010. Descriptive analysis, heat map visualization, and multinomial logistic regression were performed. The results show a complex and dynamic association between disability and parenthood. Starting on disability benefits at the age of 20–25 years was associated with a reduced chance of having children during the follow-up duration (≤42 years). Interestingly, another pattern was also revealed, and individuals who had their first child as teenagers (aged 13–19 years) were at higher odds of starting to receive disability benefits during their 30s and 40s compared to the rest of the study population. This is the first study to show evidence of a bidirectional nature of the association between age at starting to use disability benefits and the age of having a first child. Our findings demonstrate the potential of using heatmaps and multinomial regression on time-to-event data to examine bidirectional relationships between various factors investigated across several disciplines.