Physical

• Zygote


  Fertilized egg
• Fathers contribute the sex of the baby because the woman will give an x no matter what
• Germinal period

  1st stage. Cells are least vulnerable to environmental change, because of how small and protected they are, but this is also where chromosomal abnormalities start
• Parents can have recessive mutations in their genotypes that don't affect their phenotypes, but if each one gives the child the recessive allele, its phenotype will express the mutation, possibly leading to disease or impairment
• Placenta


  Sac filled with amniotic fluid that a baby is in that gives it everything she ingests or does through the umbilical cord
• Tetratogens


  Any environmental substance that reaches the embryo or the fetus that could cause harm, like alcohol or tobacco
• Embryonic stage


  2nd stage. Provided nourishment from placenta, organs start to form, neural tube closes, heart starts to beat
• Embryonic stage


  2nd-8th week of pregnancy
• Fetal stage


  9 weeks to term
• Fetal stage


  3rd stage, sex organs differentiate, digits, hearing, lungs and muscles develop, brain undergoes rapid growth