FSH is regarded as one of the most vital sexual developmental and reproductive hormones among women. However, it also plays a vital role in the sexual health of men where it is responsible for the onset of their pubertal, sexual growth. Yes, FSH testing is mainly limited to women, particular those who are above the age of 45 years or those who are finding it difficult to get pregnant since this hormone significantly impacts the female reproductive health to the extent of literally defining their ability to conceive.Please note that some degree of changes in the level of follicle stimulating hormone is not a matter of concern. In fact, most people witness a similar pattern wherein the concentration tends to dip and rise repeatedly throughout their life cycle. This is mainly because FSH is directly related with the stimulation of sexual growth and advancement of reproductive health traits across both genders. During the pubertal years, the overall hormonal volume tends to rise sharply. This is an unavoidable phase where follicle-stimulating-hormone in coordination with testosterone in males and progesterone, luteinizing hormone and estrogen in females regulates the development of primary & secondary sexual processes such as spermatogenesis in young boys and initiation of menstruation in young girls.From puberty onwards, FSH levels tend to rise gradually and eventually reach a gradient wherein the overall concentration tends to remain somewhat constant. Problems are noted only when there is a significant dip or a sharp rise in the overall concentration. While slightly lower concentrations are not seen as a major fertility deterrent, at least among women, they can impact the quality of the sperm among grown men. On the contrary, every bit of rise beyond the maximum required benchmark is seen as a major roadblock towards conceiving in females. This is most evident in ladies who are approaching menopause or menopausal women who usually have higher-than-usual concentrations and find it rather difficult to conceive without assistive reproductive treatments or some sort of fertility aid.In fact LH-FSH testing that is ordered as a part of start fertility treatments and pre-pregnancy phase is conducted with the sole purpose of ensuring that the levels are not beyond the usual range. The opposite of this scenario, i.e. fertility problems due to low follicle stimulating hormone concentrations, are quite rare but have been noted. Here, lower concentrations make the ovulation process difficult. Such women might show phases of absolute absence of ovulation, i.e. no fertilizable healthy eggs are present, called anovulation.Problems in the ovulation process also suggest poor menstrual health and irregular periods further retard the chances of conceiving in a normal manner. The bigger health risk with higher-than-usual levels is the increased susceptibility to develop ovarian cancers. Please note that phases of high FSH secretion are controlled by the pituitary gland that tries to revive the menopausal ovaries suffering from a dip in other, reproductive hormone(s) like progesterone and estrogen. The increased secretion means that ovaries are overwhelmed in the absence of counter-balancing hormones like LH, progesterone and estrogen, raising the likelihood of ovarian cysts or tumors developing.This is why most fertility specialists opine that the overall concentration of follicle stimulating hormone and its ratio with LH defines the quality of eggs, i.e. their ability to sustain fertilization and hence, pregnancy.