Astanga Hrudaya
अत एव च शुक्रस्य बाहुल्याज्जायते पुमान्। रक्तस्य स्त्री, तयोः साम्ये क्लीबः शुक्रार्तवे पुनः॥५॥
By the same docrine (of the effect being similar to the cause) a male child be produced when sukra (semen) is more, a female when rakta (menstrual blood) is more a and a eunch (child neither definitely male nor definitely female but having features of both sex, in other words a hermaphrodite) when both are equal (cause for manifestation of multiple embryos) shukra and artava
english translation