raging-liberal-hard-on:

Zygote: single cell that contains two copies of chromosomes, one from one parent, and one from the other. In a week, the zygote undergoes rapid cell division, which leads us to..

Blastocyst: Rapidly dividing group of cells, which, after some time, splits itself in half. One half will later become the placenta and the other is to become the fetus. However, before that happens..

Embryo: 12 days after fertilization, the embryo (future fetus) is about the size of a grain of rice. Its surface features and major organs start to take shape at this point. This is what goes on in the first month of development. During the second month, the development of the embryo kicks up, developing major limbs and gaining a heartbeat. As the eighth week draws to a close, the embryo is now called a..

Fetus: The (now) fetus continues its journey of development. Its reproductive organs are forming, and in month three is only about three inches long. This baby-to-be (AKA, fetus) continues on for the next six months, continuing to develop all the parts required for birth and then viola…

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Neonate: Also commonly known as a newborn infant, or an infant who is less than a month old. 

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Infant:  n, a child who is in the earliest stage of extrauterine life, a time extending from the first month after birth to approximately 12 months of age, when the baby is able to assume an erect posture.

A child in the earliest period of life, especially before he or she can walk.

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