Estrogen especially estradiol is necessary for creating a healthy sperm. In case of high level of estrogen, sperm levels in semen may fall.
The function of estradiol varies depending on the cells in which it is being produced. In testicular cells, estradiol is known to regulate numerous aspects of spermatogenesis (the process in which sperms are produced). Estradiol is involved in the modulation of cell communication of Sertoli cells (cell of the testicles that is part of a seminiferous tubule and helps in the process of spermatogenesis) and in the regulation of Leydig cell (cells in testicles which are producing testosterone) function.
In the efferent ductules (connect the rete testis with the initial section of the epididymis), estradiol is involved in the reabsorption of fluids, thus, affecting sperm concentration, motility and morphology.
Any disruption in processes of sperm development or their transport to the uterus due to high levels of estrogen can lead to fertility problems. There is lower possibility of natural conception, because the sperm is no able to reach the egg inside the fallopian tube, where the fertilization occurs.
Estradiol levels in female may provide useful information for the evaluation of ovarian reserve. High levels may show poor ovarian reserve (a condition of low fertility characterized by low numbers of remaining oocytes in the ovaries). With low count of oocytes, there is lower possibility to conceive naturally.