Kṛṣṇa says, you'll find, māṁ hi pārtha vyapāśritya ye 'pi syuḥ pāpa-yonayaḥ (BG 9.32). Pāpa-yoni. To take birth low-grade family, or animal family, these are called pāpa-yoni. Kṛṣṇa says that it doesn't matter if one is born in the pāpa-yoni, low-grade family. It doesn't matter. Māṁ hi pārtha vyapāśritya ye 'pi syuḥ pāpa-yonayaḥ. In the human society, striyaḥ śūdrās tathā vaiśyāḥ, even woman and śūdra and vaiśya, they are also taken in the category of pāpa-yoni. Pāpa-yoni means their intelligence is not very sharp. That is called pāpa-yoni. And a brāhmaṇa means to become very, very highly intellectual. That is called brāhmaṇa. Because he'll understand Brahman.
To understand Brahman is not the business of teeny brain. Alpa-medhasam (BG 7.23). There are two Sanskrit words: alpa-medhasa and su-medhasa. Alpa-medhasa means having little brain substance. Physiologically, within the brain there are brain substance. It is found that the brain substance in man is found up to sixty-four ounce. They are very highly intellectual persons. And in woman the brain substance is not found more than thirty-four ounce. You'll find, therefore, that there is no very great scientist, mathematician, philosopher among women. You'll never find, because their brain substance cannot go. Artificially do not try to become equal with men. That is not allowed in the Vedic śāstra. Na striyaṁ svatantratām arhati (Manu-saṁhitā). That is called śāstra.