For those who wants to know more :
The Filial Piety Sutra
The Buddha Speaks about the Deep Kindness of Parents and the Difficulty in Repaying it.
The Buddha told Ananda, "Although all of you are my foremost disciples and have been members of the Sangha for a long time, you still have not achieved far-reaching understanding. This pile of bones could have belonged to my ancestors from former lives. They could have been my parents in many past lives. That is the reason I now bow to them." The Buddha continued speaking to Ananda, "These bones we are looking at can be divided into two groups. One group is composed of the bones of men, which are heavy and white in color. The other group is composed of the bones of women, which are light and black in color."
Ananda said to the Buddha, "World Honoured One, when men are alive in the world, they adorn their bodies with robes, belts, shoes, hats and other fine attire, so that they clearly assume a male appearance. When women are alive, they put on cosmetics, perfumes, powders, and elegant fragrances to adorn their bodies, so that they clearly assume a female appearance. Yet, once man and women die, all that is left are their bones. How does one tell them apart? Please teach us how you are able to distinguish them."
The Buddha answered Ananda, "If when men are in the world, they enter temples, listen to explanations of Sutras and Vinaya texts, make obeisance to the Triple Gem, and recite the Buddha's names, then when they die, their bones will be heavy and white in colour. Most women in the world have little wisdom and are saturated with emotion. They give birth to and raise children, feeling that this is their duty. Each child relies on its mother's milk for life and nourishment, and that milk is a transformation of the mother's blood. Each child can drink up to one thousand two hundred gallons of its mother's milk. Because of this drain on the mother's body whereby the child takes milk for its nourishment, the mother becomes worn and haggard and so her bones turn black in colour and are light in weight."
When Ananda heard these words, he felt a pain in his heart as if he had been stabbled and wept silently. He said to the World Honoured One, "How can one repay one's mother's kindness and virtue?"
The Buddha told Ananda, "Listen well, and I will explain it for you in detail. The fetus grows in its mother's womb for ten lunar months. What bitterness she goes though while it dwells there! In the first month of pregnancy, the life of the fetus is as precarious as a dewdrop on grass: how likely that it will not last from morning to evening but will evaporate by midday!"
"During the second lunar month, the embryo congeals like curds. In the third month it is like coagulated blood. During the fourth month of pregnancy, the fetus begins to assume a slightly human form. During the fifth month in the womb, the child's five limbs- two legs, two arms, and a head- start to take shape. In the sixth lunar month of pregnancy, the child begins to develop the essences of the six sense faculties: the eyes, ears, nose, tongue, body and mind. During the seventh month, the three hundred sixty bones and joints are formed, and the eighty-four thousand hair pores are also complete. In the eight lunar month of the pregnancy, the intellect and the nine apertures are formed. By the ninth month the fetus has learned to assimilate the different nutrients of the foods it eats. For example, it can assimilate the essence of peaches, pears, certain plant roots and the five kinds of grains."
"Inside the mother's body, the solid internal organs used for storing hang downward, while the hollow internal organs used for processing, spiral upward. These can be likened to three mountains, which arise from the face of the earth. We can call these mountains Mount Sumeru, Karma Mountain, and Blood Mountain. These analogous mountains come together and form a single range in a pattern of upward peaks and downward valleys. So too, the coagulation of the mother's blood from her internal organs forms a single substance, which becomes the child's food."
"During the tenth month of pregnancy, the body of the fetus is completed and ready to be born. If the child is extremely filial, it will emerge with palms joined together in respect and the birth will be peaceful and auspicious. The mother will remain uninjured by the birth and will not suffer pain. However, if the child is extremely rebellious in nature, to the extent that it is capable of committing the five rebellious acts*, then it will injure its mother's womb, rip apart its mother's heart and liver, or get entangled in its mother's bones. The birth will feel like the slices of a thousand knives or like ten thousand sharp swords stabbing her heart. Those are the agonies involved in the birth of a defiant and rebellious child."