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The percentage risk of a birth defect for a human pregnancy that goes to full term even when the mother is young and healthy. | about 2-3% |
The number of chromosomal abnormalities that are now identifiable by sampling embryonic or fetal cells within the uterus of a mother. (Note: This question is not asking about the number of genetic disorders of all types.) | 80+ |
The gender of babies that are at the highest risk for X-linked genetic disorders. | male |
The number of known human genetic disorders. | 5,000+ |
A diagnostic procedure for pregnant women to determine whether or not their fetuses have gross chromosomal anomalies. It involves sampling the liquid immediately surrounding a fetus within the amnion. This fluid is usually extracted through the mother's abdominal and uterine walls with a hypodermic needle. |
amniocentesis |
The fluid surrounding a fetus inside the amnion in its mother’s uterus. It mostly consists of fetal urine, but also contains some fetal skin cells. | amniotic fluid |
A diagnostic procedure for pregnant women to determine whether or not their fetuses have gross chromosomal anomalies. It involves collecting a small sample of chorion cells for karyotyping. The biopsy usually is done by inserting a small flexible plastic tube through the vagina and the cervix of the uterus to draw out a sample of chorion tissue. | chorionic villi sampling (or biopsy) |
A routine diagnostic procedure for pregnant women used to determine whether or not their fetuses have gross chromosomal anomalies. For this procedure, blood is drawn from a pregnant woman in order to determine the amount of certain proteins that have leaked into her system from her unborn child. | alpha-feto protein sampling |
The general term for a chromosomal abnormality in which there is an addition or loss of chromosomes within a set (e.g., 23 + 22 or 23 + 24 in humans). Down syndrome is most often the result of this kind of error. | aneuploidy |
The general term for a chromosomal abnormality in which there are extra complete multiples of chromosome sets (e.g., 23 + 23 + 23 in humans). | Polyploidy |
A genetic pattern in which an individual has two distinct cell groupings--one with normal cells and another with a genetic problem. For instance, some people with Down syndrome produce both normal somatic cells and cells with an extra chromosome 21. | genetic mosaicism or mosaic pattern |
The process of removing a tissue sample from a living organism for diagnostic examination (e.g., chorionic villi sampling). | biopsy |