Background: Klinefelter's syndrome is caused by the presence of one or more extra copies of the X chromosome in a male's cells. Extra genetic material from the X chromosome interferes with male sexual development, preventing the testicles from functioning normally and reducing the levels of testosterone. Triple X syndrome (trisomy X) results from an extra copy of the X chromosome in each of a female's cells. Females with trisomy X have a lower IQ than their siblings. Turner syndrome results when each of a female's cells has one normal X chromosome and the other sex chromosome is missing or altered. The missing genetic material affects development and causes the characteristic features of the condition, including short stature and infertility.

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would have lower level of testosterone, patient A or patient C?
Answer: patient A

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would have higher level of testosterone, patient A or patient C?
Answer: patient C

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Would patient A have higher or lower level of testosterone than patient C?
Answer: lower

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Would patient C have higher or lower level of testosterone than patient A?
Answer: higher

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would most likely be shorter, patient B or patient D?
Answer: patient B

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would most likely be taller, patient B or patient D?
Answer: patient D

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Would patient B be shorter or taller than patient D?
Answer: shorter

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Would patient D be shorter or taller than patient B?
Answer: taller

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would have extra copies of X chromosome, patient A or patient B?
Answer: patient A

Situation: David is a physician with the children's hospital. He is seeing four patients, patient A, patient B, patient C, and patient D. Patient A is a male with Klinefelter's syndrome. Patient B is female with Turner syndrome. Patient C is a male and does not have any of these illnesses. Patient D is a female and she too does not have any of these illnesses.

Question: Which patient would not have extra copies of X chromosome, patient A or patient B?
Answer: patient B