Abstract: The present invention relates to methods for modulating progestagen signaling for treating neurological disorders or neurodegenerative disease, or preventing or delaying its onset in individuals deemed by competent observation and testing to be susceptible thereto. Progestagens can be administered to elevate serum and brain levels of progestagens and induce neurogenesis. Progestagen therapy may prevent some of the neurodegenerative and cognitive changes associated with developmental and aging associated neurological disorders and neurodegenerative diseases. Progestagen therapy together with suppression of GnRH, kisspeptin, LH and/or FSH signaling also may be used for treating neurological disorders or neurodegenerative diseases. The invention also relates to methods for inhibiting or delaying blastulation during embryogenesis, and neurogenesis during embryogenesis, fetal, neonatal, childhood, puberty or adult life.