Humans are viviparous beings; unlike birds or frogs who lay eggs, we carry our offspring within the womb until they are fully matured. As such, there is an intimate connection—emotionally, mentally, and physically—to our offspring. What that also means is that the process of fertility, before and after conception, is strongly dependent on the health of the mother. Her ability to deliver nutrients through plasma (rasa dhatu) can profoundly impact her fertility. Just as in gardening, without moisture and rich nutrients, the soil cannot nourish a seed into fruition no matter how strong the seed is. This is the importance of ambu, one of four essential ingredients to fertility along with rtu (timing), kshetra (field), and bij (seed).