A. In Vitro Fertilization
1. About 15 percent of American couples are infertile.
2. The procedure involves removing oocytes and placing them in a solution with sperm; if fertilization occurs, zygotes are carefully tended until a two to four day old embryo can be transferred to the mother's uterus.
3. Externally conceived embryos implant successfully in only about 20 percent of the attempts.
B. Intrafallopian Transfers
1. In GIFT (gamete intrafallopian transfer) a couple's sperm and oocytes are collected and placed in an oviduct in hopes of achieving fertilization.
2. In ZIFT (zygote intrafallopian transfer), fertilization is achieved in a laboratory dish followed by transfer of the zygote to an oviduct.
C. Artificial insemination is the placing of semen in the vagina or uterus by mechanical means at the time of ovulation.
Human in the Age of Mechanical Reproduction : A 1998 Discover article that describes some of the new technologies.
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