Reproduction is the origination of new organisms from pre-existing ones. Among more than 35 separated forms of reproduction including several types of gamogony, parthenogenesis, agamogenesis, fission and division, and plas- motomy, the bisexual mode of reproduction via fertilization provides genetic variability that allows species to adapt quickly to competitive and constantly changing environments. Several excellent reviews and books have been written in the past to analyse the mechanisms of fertilization in different eukaryotic species. During the last few years, however, renewed attention...

The increasing awareness on the varied consequences of hypogonadism in distinct organs and systems has supported the notion of estrogens as systemic agents. This observation is congruent with the variety of tissues affected by - trogens when used in hormone therapy formulations on hypogonadic women. Apart from the genital tract and the breast, recognized as traditional targets for estrogens, the skeleton, the vascular tree, or the central nervous system, are good examples of territories that have demonstrated sensitivity to estrogens. This evidence has created great interest, as shown by the...