Ashtangasamgraha 2.22_2

2.22_2

yadā strī prathamaṃ kṛtārthā bhavati tataḥ puruṣeṇa paścācchukramutsṛṣṭaṃ harṣānavasthitacetasaḥ striyā vāto viguṇīkaroti puṃstvavāhīni srotāṃsi copahanti tadā vātendriyaṃ bhavati |

When the woman reaches climax first, and the semen is discharged later by the man, the vāta of the woman whose mind is unsettled by excitement vitiates [the semen] and damages the channels carrying masculinity; then a person of the vātendriya type is produced.