Garuḍa Purāṇa 19

Lord proceeds to explain the process of creation.  During conjugal relationship, thoughts of couple play a predominant role in their progeny.  If the conjugal relationship is made on odd nights, girls are born and on even nights, sons are born.  During the first seven days of menstrual cycle, couples should not involve in conjugality. A woman’s body generates heat during the first sixteen days after the commencement of her menstrual cycle.  If conception happens after 14th day, a virtuous son will be born. Once the foetus is formed, the woman should not be exposed to too much of sun light.  Consciousness, the purest form of which is the Lord, is in the procreative fluids of men.  The sex of the foetus is also determined by the potency of the procreative fluids of either man or woman. If man’s is potent, a son is formed and if woman’s is potent, a girl is formed. The foetus begins its formation within twenty-four hours from the time of conjugation. When the foetus develops, it absorbs all the five elements within thirty days. At the end of two months, fat and skin are formed. At the end of third month bones are formed.  Hair is formed at the end of the fourth month.  Ears, nose and stomach are formed at the end of the fifth month.  Reproductive organs are formed at the end of the seventh month.  Hands and legs are fully developed at the end of the eighth month.  During the ninth month, the child is fully developed.  At the end of the ninth month or at the beginning of the tenth month, the child is delivered. Delivery of the child takes place with the help of air.

Lord then proceeds to explain how the five elements (ākāśa, air, fire, water and earth) form different parts of the body.  Sound, gravity, hearing and support are the qualities of ether (ākāśa). Love, hatred, fear and illusion are the qualities of air. Saliva, urine, bone marrow and blood are the qualities of water. Hunger, thirst, sluggishness and brilliance are the factors of fire. Exercising and other actions are the qualities of earth.  Lord then talks about the organs of action and the organs of perception.  There are ten principle nāḍī-s - iḍā, piṅgala, suṣumna, gāndhārī, hasti-jihvā, pūṣā, yaśā, alambuś,a kuhū and śaṅkhinī.  Similarly prāṇa-s are also ten types - prāṇa, apāna, samāna, udāna, vyāna, nāga, kūrma, kṛkāra, devatatta and dhanañjaya.  With the help of air, the assimilated food, in association with these nāḍī-s and prāṇa-s distribute the digested food to various parts of the body.  The unassimilated food (or the remains of the digested food) is egested from the body, predominantly through the two excretory organs. Lord says that there are thirty-five million hair, thirty two teeth, twenty nails, seven hundred thousand hair in the face and the  head of a physical body.  

Pleasure and pain are the result of one’s karma.  Foetus and the fully grown-up child in the womb is nourished through the umbilical cord attached to its mother.  The foetus consumes whatever is consumed by the mother.  The soul (subtle body) recollects its actions during its previous lives, while sojourning in the womb.  By getting afflicted by its karmas, it decides that it should not commit further sins during the ensuing life. Though the child loses its consciousness at the time of ejection from the womb, it regains its consciousness immediately after inhaling its first breath. Immediately, after the child is out of the womb, it forgets all its past life and hence its decision as to not to make any further sins also goes haywire. The child is deluded by māyā and continues to remain in that state throughout the process of aging, until its death.  It is again reborn, and this cycle continues until it attains liberation.  If there is any interim period between death and the next birth, its subtle body undergoes either pleasure or pain, depending upon its karmic account.  If the karmic account is good, one tends to undergo pleasure both on earth and in heaven.  If the karmic account is bad, then it undergoes sufferings both on earth and in hell.  There are fourteen types of worlds, seven upper worlds and seven lower worlds. The seven vyāhṛti-s of the famous Gāyatrī mantra are the seven upper worlds.  Each of these worlds is related to fourteen parts of the body.  In the same way, the nine planets used in astrology also represent nine parts of the body.  

The entire cosmos is in the human body and the Soul within is the God.  There is no difference between cosmos and human body except that the former is the macrocosm and latter is the microcosm.  The cosmic Lord is in no way different from the Lord within the human body or for that matter, in any living being.  In order to differentiate (arising out of ignorance), Cosmic Lord is represented by Self and empirical self is represented by self.