Pennsylvanians for Human Life Logo - PHL provides educational information 
                                              to approximately 35,000 people each 
                                              year. Pennsylvanians for Human Life Logo - PHL provides educational information 
                                              to approximately 35,000 people each 

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Fetal Development:


Fetology is the study of unborn babies. Scientific evidence confirms that human life begins at conception.


Conception takes place in the fallopian tube when the mother’s egg (ovum) and the father’s sperm meet, each contributing 23 chromosomes -- result in the creation of a brand new cell. The father’s 23 chromosomes include either the X or Y chromosome, which will determine the gender of the baby.

The human ovum is about the size of a pencil point!
Fallopian tube is approximately 4” long and can be compared to a bristle of a hair brush.
All the sperm cells in the world could fit into a thimble; all the eggs in the world could fit into a cookie jar!

Egg survives 12-24 hours only.


ZYGOTE is the name used to describe the developing baby for the first 2 weeks.

At this point baby has its own DNA - genetic make-up; gender and blood type. (often different than the mom or dad’s). The baby’s heart is BEATING before the mother misses her first period.

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MITOSIS- the process of cells multiplying during the ZYGOTE stage.

At no time after conception is this child a part of the woman’s body. It is merely using her womb as an anchorage; Mothers’ contributions are nutrition and oxygen. Please note - when a pregnant woman is hospitalized, there are two charts at the end of her bed because the doctors know that there are two patients.

Two different doctors will care for the woman - a pediatrician for the baby and an obstetrician for the woman.

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EMBRYO is term used to describe the developing baby from 2 weeks - 8 weeks. The fertilized cell travels out of the fallopian tube and implants onto the wall of the uterus (womb). The umbilical cord connects baby with mother (via placenta). Trophoblast is the name of the tissue that surrounds the embryo that will turn into the placenta.

  • At 3 weeks (19 days), Doctors can hear the heartbeat;
  • At 6 weeks the brain-waves can be detected (the central nervous system is in place with a very raw system, resulting in very sensitive nerve-endings)..
  • At 7 weeks the skeletal system is complete. Baby has a mouth with lips, an early tongue.
  • At 8 weeks the fingerprints are set.

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FETUS is Latin for “little one.” This is what developing baby is called from 8 weeks to birth. At 10 weeks, every organ is in place and functioning. Bones begin to calcify at this time. The baby only grows and matures. Tiny human feet are completely formed. Fingerprints and footprints will never change for the rest of our lives.

At 10 weeks the baby is highly responsive to touch (when eyelids or palms are touched, they close). Baby can squint, swallow, stick out his tongue. Cartilage is now calcifying to become bone. The baby is sensitive to light at 16 weeks. The baby responds to sounds at 27 weeks. 2/3 of human development takes place in mother’s womb.

Photography: ©Life Issues Institute

fetus at 7 weeks from conception
7 weeks from conception

fetus at 8 weeks from conception
8 weeks from conception

fetus at 11 weeks from conception
11 weeks from conception

fetus at 14 weeks from conception
14 weeks from conception

fetus at 16 weeks from conception
16 weeks from conception

fetus at 20 weeks from conception
20 weeks from conception


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