Answer:
The correct statements are: A) Extremely high body fat decreases female fertility and B) Extremely low body fat decreases female fertility.
Step-by-step explanation:
Both underweight and overweight females suffer a decrease in their fertility. Women with a low BMI produce less estrogen than women with a normal BMI, and this can lead to amenorrhea (the lack of a menstrual cycle) which can also impact ovulation. On the other hand, women with higher BMIs may have perturbations on their hypothalamic-pituitary-ovarian axis, which is also important for the menstrual cycle and ovulation.
Body fat does have an impact on male fertility. Several studies conducted on men revealed that overweight males 1) produce lower volumes of semen, 2) have a higher incidence of low sperm count, 3) have higher chances of having azoospermia (no competent sperm in the semen), and 4) can also negatively impact the health and viability of embryos.
However, there isn't a linear relationship between body fat and the rate of conception.