Start of Life
How you began..
- Each human being begins life as a single cell at the moment of conception, when their father's sperm fertilizes their mother's egg. A unique living human being, already either male or female - has been created. The cell divides repeatedly and organisation begins.
- Week 2 (days 6-12)
The embryo implants in the lining of his or her mother's womb.
- Week 3 (days 24-28)
The head is distinct, limb buds are visible; the early eyes, liver, brain, lungs and kidneys are present, and the heart is beating.
- Week 6 (days 44-46)
Fingers and toes are distinct, the outer parts of the ears are well advanced and the eyelids have almost covered the eyes.
The first movements can be seen on ultrasound scans. The baby now has unique fingerprints!
- Month 3
From week 9 the unborn child is called a 'fetus' which means 'little one'. From week 11 the baby can produce complex facial expressions and even smile.
- Month 4
By week 16 the baby generally weighs around 200g (7oz). The heart pumps around 30 litres of the baby's own blood every day. By now the baby appears to respond to sound and light.
The baby's fingernails and hair begin to grow. (Notice the eyeborw in the picutre here?)
- Month 6
The baby opens his or her eyes.
- Months 7-9
The baby gains weight and matures, developing immunity to various diseases.
The individual who began life as a single cell now has around 200 million cells.
In 2013 researchers estimated that the average (adult male) individual may have around 37 trillion cells.
Does counting cells or changing labels like embryo, fetus, baby, child, adult, in any way impact your uniqueness as a human individual?