A Closer Look at
Conception
Chapter 5 Section 2
The Genetic Package
• Chromosomes- tiny threadlike
particles in the nucleus of every
cell.
• Come in 23 pairs (babies receive 46)
• Genes- units that determine the
child’s inherited characteristics.
(genes make up chromosomes as
beads make up a necklace)
Dominant and Recessive
Genes
• Dominant genesstronger genes
(Brown hair or brown eyes)
•
Recessive genesweaker gene
(Blonde hair or blue eyes)
Multiple Births
• When cells continue to
divide and grow into
separate embryos!
• Identical Twins
• Fraternal Twins
• About 2.5% births are twin
births in the United States
(fraternal twins occur three
times more often)
• Babies are more likely to
be premature
• Mother is more likely to
experience excessive
bleeding
Infertility
• Infertility- the inability to become
pregnant
• Surgery or medication may solve the
problem
• Fertility drugs- help stimulate a
woman’s ovaries to release eggs
• Fertility drugs may cause serious side
effects (lung problems, abdominal
pain, diarrhea etc..) and increase the
chances of multiple birth
Options for Infertile Couples
1. Adoption
2. Artificial Insemination
a doctor injects sperm
into a woman’s uterus
with a special needle.
It can come from the
husband or a donor
Options for Infertile Couples
• In vitro fertilizationthis process is used
when a woman has
damaged fallopian
tubes that prevent
pregnancy. In a small
glass dish the doctor
combines a mature egg
from the woman and
sperm from her
husband. If fertilization
takes place the doctor
places the zygote in the
woman’s uterus
Options for Infertile Couples
• Ovum transfer- procedure
uses an egg taken from a
female donor and in vitro
fertilization. It may be used
by women who lack working
ovaries or who have
inherited disorders
• Surrogate mother- mother is
a woman who becomes
pregnant for another
couple. She may carry a
couples fertilized egg.
Do you think these
practices
raise many ethical
questions?