PSY 3121 Lecture Notes - Lecture 3: Prenatal Development, Pseudohermaphroditism, Late-Onset Hypogonadism
16 May 2018
School
Department
Course
Professor
PSY3121A Dr. Mary-Theresa Howard
Hormones & Chromosomes 09.05.18
Biology and Gender
Development – process that is qualitative and quantitative
• Male sperm cell determines sex of offspring and chromosomes are determinants of sexual characteristics
• Outcome of sexual development is mediated by female viability and hormones
• Genes determine if embryo is male (XY) or female (XX), as embryo develops they receive hormones
o Genes require a boost of hormones to develop a male (testosterone) or a female (estrogen)
• Complications occur when the genes are abnormal or hormone levels are incorrect
o Turers sdroe, to o has higher testosteroe leels
Prenatal development – female pattern is standard
• Female viability – environment of conception determines sex
o tend to have more miscarriages with boys, more complications occur with baby boy deliveries
o X bearing sperm are more viable
• hormonal abnormalities - steroid hormones important for sexual development and behavior include
androgens, estrogens, and progestins; women produce more estrogens and progestins
o prenatal production affects the brains and fetuses to organize along female or male pattern
• fetal abnormalities – prenatal period consists of germinal, embryonic, and fetal stages
o androgenital syndrome has a link with chromosomal abnormalities and hormones (androgens
and cortisol)
• sex chromosomal abnormalities – genetic inheritance of either XX or XY chromosome of pair 23
o i.e turers sdroe leads to phsial ad horoal aoralities due to seod X
chromosome that is missing or defective
o embryos are sexually dimorphic until 6 weeks gestation
▪ XY produce androgens and Mullerian-inhibiting substance during third month
(masculine fetus); XX develop Mullerian structures (ovaries, tubes, uterus, upper vagina)
o Noral hroosoes dot guaratee oral deelopet
▪ hermaphroditism and pseudohermaphroditism have the physiology of both sexes
o things can go wrong at any stage – chromosomes – too few or too many produces problems with
the development of internal and external genitalia, developmental disorders (intelligence),
Turners (single X) and Klinefelters (XXY)
Infancy and childhood
• more males are conceived but more males die before birth; females have fewer problems during birth
and labour is shorter and have fewer defects
• females have longer life expectancy, fewer congenital disorders, less likely to have SIDS, or be hyperactive
• females are more mature at birth, more advanced skeletal and neurological systems; mature faster
• on avg are taller at 7-10 years of age
• autism could be due to gestational complications
Adolescence and Young adulthood – during puberty hormones activate internal genitalia and develop secondary
sex characteristics
• puberty occurs at 11-17 yrs old in girls; 98% of height reached at 16.25 years old
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