1. A Closer Look at Conception
Section 5-2
The Developing Child

2. The Genetic Package 46 chromosomes Dominant = stronger gene
23 pairs
Dominant = stronger gene
Recessive = weaker gene
A person receives two copies of a gene-one from the mother and one from the father

3. The Genetic Package
The father’s sperm and the mother’s ovum both contribute a chromosome to each pair.
When both are the same, the child has that characteristic (two genes for blue eyes give the child blue eyes).

4. Sex Chromosome Every ovum contains an X chromosome.
Each sperm cell contains either an X or Y chromosome.
If sperm carries X…results in an XX combination…becomes a girl.
If sperm carries Y…results in XY combination…becomes a boy.

5. Multiple Births Identical Twins
When a fertilized egg starts growing, it divides into two cells…these cells continue to divide.
Sometimes the mass of cells splits in half soon after fertilization…results in identical twins
Always the same sex and have very similar characteristics because both began as one zygote

7. Multiple Births Fraternal Twins
2 eggs are released from the ovary and both are fertilized by different sperm
No more alike than siblings born at different times

8. Infertility Adoption:
The couple legally takes all responsibilities and rights for raising a child already born

9. Infertility Artificial Insemination
A doctor injects sperm into a woman’s uterus with a special needle
The sperm may be the husband’s.
If he has a history of genetic disorders or is unable to produce sperm…the sperm may come from another male…called a donor

10. Infertility In vitro fertilization
When the woman has damaged fallopian tubes that prevent pregnancy.
In a small glass dish, a doctor combines a mature egg from the woman and sperm from her husband or donor.
If fertilization takes place, the doctor places the zygote in the woman’s uterus.
If the zygote attaches to the uterine wall, normal pregnancy takes place.

11. Infertility Ovum Transfer
May be used by women who lack working ovaries or who have inherited disorders.
The procedure uses an egg taken from a female donor combined with in vitro fertilization.

12. Infertility Surrogate Mother
This occurs when another woman becomes pregnant for another couple.
Artificial insemination, in vitro fertilization, and/or ovum transfer may be used.
When the woman gives birth, she gives the baby to the couple.
Legal arrangements are made and they must meet state laws.

13. Problems in Prenatal Development
Losing a baby…can cause a great deal of pain…usually happens naturally
Miscarriage
When the developing baby dies between 1-20 weeks of pregnancy
Stillbirth
When the developing baby dies after 20 weeks of pregnancy

14. Causes of Birth Defects
Hereditary Causes
Genes may be imperfect (dominant or recessive)
Environmental Causes
Nutritional balance of pregnant woman
Diseases or infections during pregnancy
Harmful substances during pregnancy
Alcohol
Tobacco
Drugs
Some medications can hurt the baby
Exposure to outside hazards…radiation

15. Examples of Birth Defects
Cerebral Palsy
Cleft Lip/Palate
Cystic Fibrosis
Down Syndrome
Muscular Dystrophy
Sickle Cell Anemia
Spina Bifida or Hydrocephalus
Tay Sachs Disease

16. Prenatal Tests Ultrasound
Uses sound waves to make a video image of an unborn baby to check for specific health problems
It can show whether the fetus is developing on schedule
Can confirm: due date, multiples, gender

18. Prenatal Tests Amniocentesis
The process of withdrawing a sample of the amniotic fluid surrounding an unborn baby
Can test the amniotic fluid for indications of specific birth defects or other health problems
Risk: 1 in every 200 can result in miscarriage…only performed when there is a strong medical reason

20. Prenatal Tests Chronic Villi Sampling
Used to test for specific birth defects
Can be done earlier than an amniocentesis
Guided by an ultra sound image, a doctor inserts a small tube through the vagina into the uterus…then samples of the tissue are snipped or suctioned off for analysis.

21. 3-D Ultrasound compared to traditional Ultrasound