Phytoestrogens are natural estrogenic agents present in plants. Phytoestrogens are any plant compounds structurally and/or functionally similar to ovarian and placental estrogens and their active metabolites.Sesamumindicum is one of the phytoestrogen containing seeds used by man for food and medicinal purposes. Researches have shown that phytoestrogens present in plants might have both fertility-enhancing and anti-fertility effects. Present studies evaluated the mean lethal dose of the hydroethanolic seed extract of sesame and the effects of the extract on some reproductive parameters of female albino rats. Cycling female rats weighing 120-140g were used for the studies. For the ovulation study, twenty (20) female rats were divided into four (4) groups of five (5) rats groups II, III and IV received 100, 300 and 500 mg/kg of seeds extract of S. indicumorally respectively. The animals were dosed at 4 hourly interval for 24 hours. Animals were sacrificed the following morning. For the hormonal level study, the extract was administered orally to three (3) experimental groups of five (5) female rats at doses of 100, 300 and 500 mg/kg once daily while control group received distilled water at dose of 1ml/kg for 30 days. The animals were subsequently sacrificed in the morning of the day after the last administration. For studies on pregnancy outcome, the extract was administered orally four (4) groups of five (5) pregnant rats each. Administration was done once daily from day 1-7 of pregnancy as follows: group I: distilled water (1 ml/kg), group II: 100 mg/kg, group III: 300 mg/kg and group IV 500 mg/kg respectively, with seeds extract of S. indicum.

Hormones are intimately involved in our sex lives, as well as all other aspects of ourlives, from intrauterine life to death. Of these, the most important are the socalledsex hormones. Mammalian sexual behavior is controlled by these gonadal steroids actingat the level of the central nervous system. They are divided into the male hormones (orandrogens) and the female hormones. While, both sexes produce both types, those corresponding to the appropriate sex predominate (in most cases) (Wierman, 2007). Women produce a number of hormones specific to them, particularly during their childbearing years. The two best-known female hormones are estrogen and progesterone, sometimes also referred to as sex hormones. These are produced predominantly in the ovaries, although the adrenal glands and the placenta of pregnant women also secrete them. Some research has indicated that estrogen can be manufactured in the brain as well (Haybach, 2010).