Fraternal twins, which are nondientical genetically, arise when two oocytes mature, are released, and are fertilized at the same time. Such twins run in families. The incidence varies among ethnic groups and is highest among blacks and lowest in Asians. Variation may be an outcome of differences in gene products that affect the FSH level in blood. Explain how a high FSH level would increase the likelihood of fraternal twins.
2006-11-20 22:08:46 · 2 answers · asked by aerojanie 1 in Science & Mathematics ➔ Biology
FSH levels affect ovulation. Higher FSH levels, naturally occurring or medically introduced in fertility drugs, will increase ovulation, causing a higher rate of multiple births -- fraternal twins, triplets, etc.
2006-11-20 22:34:08 · answer #1 · answered by joanmazza 5 · 2⤊ 0⤋
FSH stimulates the development of the ovarian follicles, and the subsequent release of the egg. With a high FSH, there is a slightly higher chance of stimulating the release of eggs from both ovaries at the same time, hence there will be two non-indetical eggs just hanging around waiting for fertilisation.
2006-11-20 22:37:04 · answer #2 · answered by Labsci 7 · 0⤊ 0⤋