Cloning: Taking body (i.e., non-sex) cells from an adult and introducing them
into an unfertilized egg that has had its genetic material removed, and then
encouraging embryo development.
Cytoplasm: The complex of organic and inorganic substances within a cell
outside of the nucleus.
Cytoplasmic transfer: A technique in which cytoplasm from a donor egg is drawn
into a pipette containing a single sperm from the male partner, after which
that donated cytoplasm and the sperm are injected into the patient's
Frozen embryos: Specialists may freeze additional embryos from a woman's cycle
for later use. They may also freeze embryos of a donor in order to have them
ready to place in a surrogate mother's uterus at the appropriate moment in the
surrogate's natural or hormone-replaced cycle.
In vitro fertilization: Taking eggs from a woman, fertilizing them in the
laboratory with a man's sperm, and returning the resulting embryos to her
uterus several days later.
Nuclear transfer: In his still-experimental technique, Dr. Jamie Grifo of New York University Medical Center takes the nucleus
of an immature egg (i.e., one that hasn't gone through cell division) from the
mother-to-be and places it in the enucleated (nucleus-free) egg donated by a
young woman. Grifo's hope is that the technique, when perfected, will help
older women whose eggs are less than ideal have babies using a younger person's
Surrogate: A surrogate mother is one who, usually by artificial insemination or
by introduction of a fertilized egg (hers or that of a donor or the mother who
will raise the child) into her uterus, becomes pregnant and carries a baby to
term for another woman.