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In 1996, Michael R. Harrison published “Fetal Surgery” in the American Journal of Obstetrics and Gynecology. In the article, Harrison describes the importance of fetal surgery and the techniques used to correct defects in fetuses. As a fetus develops in the uterus, it can develop abnormalities that may become debilitating or fatal. Harrison discusses cases that show how physicians can use fetal surgery to repair such abnormalities, including obstructions in the heart or urinary tract, or organs or muscles whose malformations impair function.
Edmund Beecher Wilson experimented with Amphioxus (Branchiostoma) embryos in 1892 to identify what caused their cells to differentiate into new types of cells during the process of development. Wilson shook apart the cells at early stages of embryonic development, and he observed the development of the isolated cells. He observed that in the normal development of Amphioxus, all three main types of symmetry, or cleavage patterns observed in embryos, could be found. Wilson proposed a hypothesis that reformed the Mosaic Theory associated with Wilhelm Roux in Germany.
Androgen Insensitivity Syndrome (AIS) is a human disorder in which an individual's genetic sex (genotype) differs from that individual's observable secondary sex characteristics (phenotypes). A fetus with AIS is genetically male with a 46,XY genotype. The term 46,XY refers to the chromosomes found in most cells of the fetus. Most cells have a total of 46 autosomes, or non-sex chromosomes, and a pair sex chromosomes, XX for genetic females, or XY for genetic males.