Astanga Hrudaya
वीर्यवन्तं सुतं सूते ततो न्यूनाब्दयोः पुनः। रोग्यल्पायुरधन्यो वा गर्भो भवति नैव वा॥९॥
gives birth to a valiant son On the other hand, if the age is less, the offspring will be either sick, of short life span, of inauspicious nature or there may be no formation of fetus at all
english translation