The Compendium of Bheḷa 4.3

Here, one should approach a woman of a different gotra who has bathed after her fertile period; / thus she gives birth to an intelligent, healthy son.

Just as a crop does not sprout properly from a defect in the seed, / so through a defect in the mother and father the embryo perishes.

Therefore, having consumed properly nourishing food during the fertile period, the husband and wife / should enter into union in private, remembering the Lord in their minds.

There may be abnormalities or lack of conception if unwholesome tastes are consumed, / or from suppression of natural urges, or again through a disorder of the yoni.

When the yoni is afflicted by a doṣa, the embryo indeed does not stay; / likewise in an external yoni and always in an expelling one.

And in which yoni the wind receives the incoming semen, / that pregnant woman bears the embryo, endowed with pure menstrual blood.

And when that falls away, then the embryo perishes; / that is indeed wind-enlargement of the abdomen for a woman; therefore one should avoid dry things.

When semen is predominant, a male is formed; when blood [is predominant], a female; / when the two are equal, a hermaphrodite; therefore one should increase semen.

When, however, powerful wind divides the kalala into two, / twins are then produced, according to the word of Kṛṣṇa Ātreya.

There, in the part where semen is greater, a male [arises]; where blood is greater, a female; / according to this very rule one should also determine [the sex] in twins.

Wind, on the other hand, is powerful in the bodies of horses and pigs; / dividing the kalala there, it produces numerous offspring.

And when the embryo does not receive nourishment through corrupted vessel-orifices, / remaining incomplete like an elephant, it stays so for years.

When, nurtured by nourishment, it becomes full-limbed, / then the embryo, having slipped from the woman's belly, is born at the proper time.

And those twenty disorders of the yoni that are spoken of by physicians— / through these and many others, a woman's embryo suffers misfortune.

Therefore, desiring a son, one should treat these doṣas; / for through therapy, resemblance to the embryo of elephants and horses becomes pure.

Joined with wind, space, and the season, [fire] among the other deities, / born within as Jātavedas, is capable of [exerting] power.

When a man and woman in the fertile period, with serene minds, / unite in private, then the embryo becomes sāttvika.

When a man and woman in the fertile period, with violently agitated minds, / unite, then the embryo becomes rājasa.

When a man and woman in the fertile period, with deeply despondent minds, / unite in private, then the embryo becomes tāmasa.

The characteristics and the origin—thus has this been declared / of the three matrices of sattva; one should characterize mixed ones by that very means." Thus said the venerable Ātreya. / Thus ends the third chapter in the Section on the Body in Bheḷa. / Fourth chapter. / Now we shall explain the chapter on the body entitled "Aggregate of Man" (Puruṣanicaya); thus said the venerable Ātreya.