Human growth is defined as the set of stages that it goes through until it reaches maturity on the physical and emotional levels, and these growth and development processes continue over several years, until the person reaches the stage of adulthood, and each stage of growth is considered distinct. With the physical, emotional, social , and cognitive development it is associated with. 
Stages of human growth
Growth before birth
A person goes through many stages of growth and development before birth, as human growth begins during the first twenty-four hours after fertilization of the egg, followed by rapid divisions of that fertilized egg , where the embryo's organs are formed and developed during the nine months of pregnancy, before it is ready to go out into the world, and we explain The following are the most important stages of fetal growth and development during the nine months of pregnancy:  
- The first month: the first stage of human growth begins during the first month of pregnancy, when the face begins to form, red blood cells arise and begin to circulate in the body, and the primitive heart arises and begins to beat , and the size of a person at this stage is very young, as it does not exceed the size of a grain the rice.
- The second month: The development of facial features continues in the second month of pregnancy, and the hands and feet begin to emerge from the body, followed by the formation of the fingers and toes of the hands and feet, as well as the brain, spinal cord , and central nervous system tissues, in addition to the beginning of the growth of the digestive system , sensory organs, and bones.
- The third month: hands, feet and fingers grow in this month until they become fully formed, and the beginnings of teeth, nails, and ears also begin to form, and the genitals also develop during this period without the ability to determine the sex of the fetus with sonar during this stage, and the body of the fetus is still small in This stage, as it is about 10 centimeters long at the end of the third month.
- Fourth month: The fetus’s heartbeat develops during the fourth month of pregnancy, and facial features such as eyelashes and eyelids also develop, the genitals complete , teeth and bones grow to become denser than before.
- Fifth month: a person grows muscles in the fifth month of pregnancy, and becomes able to move during it, and hair grows on the head of the fetus and in other places of the body to protect it.
- Sixth month: In the sixth month, the fetus’s reactions to sounds develop. Skin also develops and fingerprints are formed. Some fetuses are born during this month, and they may survive under close care.
- The seventh month: The fetus continues to grow and store fat during the seventh month of pregnancy, and its reactions to sound, light and pain develop more, as the sense of hearing is completed at this stage, and the chance of the fetus’s survival improves in cases of premature birth in the seventh month.
- The eighth month: Growth processes continue in all parts of the body during the eighth month, and most of these organs become fully developed, the brain grows rapidly during this period, the sense of sight matures, and the body continues to store fat during this month.
- The ninth month: The lungs of the fetus grow during the last month of pregnancy, and its reactions develop during this period as well, and the fetus is ready to go out into the world, and the normal length of the fetus at the completion of the ninth month of pregnancy is between 45-50 cm, and its weight is about 3.2 kg.
The sizes of normal children vary when they are born, and their growth rate varies in the following period, and the person in the first year after birth is called the infant , and the rate of height increase in the first six months of this period is about 1.25-2.5 centimeters per month , And his weight increases by about 140-200 grams per week, and the growth process slows down slightly in the following six months, with an average increase in height of about one centimeter per month, and an increase in weight between 85-140 grams. 
Growth at this stage also includes the ability to move more, as the infant at the end of his first year is able to sit, crawl, and possibly walk , and his abilities to grasp small things develop, and his mental and social skills develop, as he begins to make some sounds and words, and is able to understand some From what those around him speak, and the infant begins to play with his family and children around him, and his five senses develop. 
The childhood stage is divided into several partial stages, the first of which is the toddler age between the ages of one and three years, which begins with the child's ability to walk, and this stage includes many developments in the child's abilities to move, speak and interact with others, in addition to emotional developments. This is followed by the pre-school stage, which extends between the ages of three and five, during which the child prepares for entry to school and the beginning of learning, and in which the child's abilities to attention and focus develop, in addition to the development of his commitment to instructions, after which the child passes the age of enrollment In the school , which extends between the ages of five and twelve, and during this stage many skills of the child develop, such as: problem-solving skills and facing challenges, in addition to self-reliance, as creativity appearsIn children at this stage, their bodies begin to develop sexually at the end, in preparation for the transition to adolescence and adulthood.  
In view of the physical growth of children, this growth rate is lower than the previous one when a person was a baby, as the rate of increase in height becomes about six centimeters per year, and remains so until reaching adulthood. 
Growth during adolescence and adulthood
The stage of adolescence starts from the age of thirteen years until the age of eighteen, and the period of adolescence is characterized by emotional development and personal growth, where a person begins to make his personal decisions, the desire for independence and not to obey the family at times, and the adolescence period ends when a person becomes an adult. 
Puberty occurs during adolescence, which is the stage that leads to fertility and sexual maturity in a person, and puberty is characterized by many changes in his body and personality, as these changes lead to the onset of fertility and the growth of secondary sexual characteristics, which are physical characteristics associated with puberty, such as: hair growth in some places The body in males and females, and the stage of puberty is associated with a rapid increase in the rate of physical growth for a period ranging between two and three years, in which a person gains from 17-18% of his height, as the bone grows and increases in density and thickness, in addition to muscle growth in males and increased fat storage In some areas of the female body, it should be noted that puberty usually begins in males between the ages of twelve and sixteen, while female puberty occurs between the ages of ten and fourteen. 
Growth of an adult human
The stage of adulthood begins at the age of eighteen years and ends with the death of a person, interspersed with the stage of middle age, and then the stage of aging, and the human body continues to grow after puberty; Where muscle mass grows until the mid-twenties, the structure of the skeleton develops up to thirty years, and after that the functions of the body begin to weaken gradually, and the pace of this weakness accelerates as the person ages, as the muscle mass begins to gradually decay, the heart muscle weakens and cholesterol is deposited in the blood vessels Little by little, in addition to the weak secretion of sex hormones with age.  
- Stephanie is in Chandler (13-6-2017), "For Growth , Stages of a HUMAN" , Www.healthfully.com , Retrieved 14-4-2019. Edited.
- "Fetal Development: Stages of Growth" , www.my.clevelandclinic.org , Retrieved 14-4-2019. Edited.
- "Slideshow: Fetal Development Month by Month" , www.webmd.com , Retrieved 14-4-2019. Edited.
- "Infant and toddler health" , www.mayoclinic.org , Retrieved 4-4-2019. Edited.
- "Infant and Newborn Development" , www.medlineplus.gov , Retrieved 14-4-2019. Edited.
- "Ages & Stages" , www.healthychildren.org , Retrieved 5-5-2019. Edited.
- "Your Child's Growth" , www.kidshealth.org , Retrieved 4-15-2019. Edited.
- Melissa Conrad Stöppler, "Puberty" , www.medicinenet.com , Retrieved 15-4-2019. Edited.
- "Adulthood" , www.britannica.com , Retrieved 15-4-2019. Edited.