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Sperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture.
Location of Clinic | ||||
Columbia, Missouri | Los Angeles, California | Minneapolis, Minnesota | New York, New York | |
Average age | 30.7 | 29.8 | 32.2 | 36.1 |
Percent nonsmokers | 79.5 | 70.5 | 85.8 | 81.6 |
Percent with history of STD | 11.4 | 12.9 | 13.6 | 15.8 |
Sperm count (million/ml) | 58.7 | 80.8 | 98.6 | 102.9 |
Percent motile sperm | 48.2 | 54.5 | 52.1 | 56.4 |
FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease.
4. Do these data support the hypothesis that living near farmlands can adversely affect male reproductive function?
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Biology: The Unity and Diversity of Life (MindTap Course List)
- Birth Defects and Multiple Births A woman who carries multiple offspring at the same time increases the risk of some birth defects. FIGURE 42.18 shows the results of Yiwei Tang's study of birth defects reported in Florida from 1W6 to 2000. Tang compared the incidence of various defects among single and multiple births. She calculated the relative risk for each type of defect based on type of birth, and corrected for other differences that might increase risk such as maternal age, income, race, and medical care during pregnancy. A relative risk of less than 1 means that multiple births pose less risk of that defect occurring. A relative risk greater than 1 means multiples are more likely to have a defect. FIGURE 42.18 Prevalence, per 10,000 live births, of various types of birth defects among multiple aria single births. Relative risk for each defect is given after researches adjusted for the motor's age, race, previous adverse pregnancy experience, education, Medicaid participation during pregnancy, as well as the infant's sex and number of siblings. 4. Does a multiple pregnancy increase the relative risk of chromosomal defects in offspring?arrow_forwardSperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture. Location of Clinic Columbia, Missouri Los Angeles, California Minneapolis, Minnesota New York, New York Average age 30.7 29.8 32.2 36.1 Percent nonsmokers 79.5 70.5 85.8 81.6 Percent with history of STD 11.4 12.9 13.6 15.8 Sperm count (million/ml) 58.7 80.8 98.6 102.9 Percent motile sperm 48.2 54.5 52.1 56.4 FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease. 2. In which cities did samples show the highest and lowest sperm motility (ability to move)?arrow_forwardSperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture. Location of Clinic Columbia, Missouri Los Angeles, California Minneapolis, Minnesota New York, New York Average age 30.7 29.8 32.2 36.1 Percent nonsmokers 79.5 70.5 85.8 81.6 Percent with history of STD 11.4 12.9 13.6 15.8 Sperm count (million/ml) 58.7 80.8 98.6 102.9 Percent motile sperm 48.2 54.5 52.1 56.4 FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease. Aging, smoking, and sexually transmitted diseases adversely affect sperm. Could differences in any of these variables explain the regional differences in sperm count?arrow_forward
- Researchers are learning how to transfer sperm-making cells from fertile male mice into infertile male mice in the hopes of learning more about reproductive abnormalities. These donor spermatogonia cells have developed into mature spermatozoa in 70% of cases, and some recipients have gone on to father pups (as baby mice are called). This new advance opens the way for a host of experimental genetic manipulations. It also offers enormous potential for correcting human genetic disease. One potentially useful human application of this procedure is treating infertile males who wish to be fathers. a. Do you foresee any ethical or legal problems with the implementation of this technique? If so, elaborate on the concerns. b. Could this procedure have the potential for misuse? If so, explain how.arrow_forwardSperm and ova are similar in terms of ________. size quantity produced per year chromosome number flagellar motilityarrow_forwardWhy do we consider a growing child to be alive, but not a growing crystal? Is abortion the taking of a human life? If so, what about a contraceptive foam that kills only sperm?arrow_forward
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- 20arrow_forwardWhy do you think that birth control law was enacted? What harm do you think it caused? When was that law overturned (and if you found U.S. states that have not overturned such a law)? And what were the reasons for the removal of that birth control law ?arrow_forwardA couple living in Florida is trying to have a baby, but they are having trouble getting pregnant. The male is very light skinned yet enjoys spending as much time as possible outdoors in the sun. From the male's perspective, why might he be contributing to the trouble with getting pregnant? Excessive ultraviolet light exposure can reduce folate levels, and folate is required for normal sperm development. Excessive heat from the sunlight inhibits normal sperm production; thus, he probably does not have enough sperm. The male does not have enough melanin production to support normal sperm development. Excessive sunlight exposure can rapidly increase folate levels, which then inhibits normal sperm development. Normal sperm development occurs best in colder temperatures; thus, living in Florida he has a reduced chance of getting his partner pregnant.arrow_forward
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