Third-stage syphilis is the most severe stage of the disease, and it is not possible to have children if one has third-stage syphilis, because syphilis can be transmitted from mother to fetus. The infectivity is particularly strong during the third stage. If a child is conceived at this time, it could lead to stillbirth. Besides stillbirth, even if the child is born by chance, they may have abnormal development or be born with diseases. This is tremendously painful and tormenting for both the parent and child. Therefore, one cannot have children with third-stage syphilis.