Changes

Effect of seasonal and individual variation on virility of a person has been mentioned. A particular code of conduct based on season has been told for coitus frequency. Such regime helps to preserve the strength of the person. According to Chakrapani, in ''Hemanta'' (early winter) and ''Shishira Ritu'' (winter) virility of a person is more. So one can have coitus regularly as per their strength in these seasons. In ''Vasanta Ritu'' (spring) coitus on every third day, and in ''Varsha Ritu'' (rainy season) in fortnight is advocated.   

Effect of seasonal and individual variation on virility of a person has been mentioned. A particular code of conduct based on season has been told for coitus frequency. Such regime helps to preserve the strength of the person. According to Chakrapani, in ''Hemanta'' (early winter) and ''Shishira Ritu'' (winter) virility of a person is more. So one can have coitus regularly as per their strength in these seasons. In ''Vasanta Ritu'' (spring) coitus on every third day, and in ''Varsha Ritu'' (rainy season) in fortnight is advocated.   

Human conception follows a seasonal rhythm. Seasonal modifications of reproductive functions and semen parameters are documented in human males. Recent trends noted a decline in relation of seasonal variation and human conception rhythm. The increased industrialization leading to increase in people being shielded from both photoperiod (by indoor work) and temperature (by heating and air conditioning) might be the reason behind this.

Human conception follows a seasonal rhythm. <ref>Cagnacci, A. and Volpe, A. (1996) Influence of melatonin and photoperiod on animal and human reproduction. J. Endocrinol. Invest., 19, 382–411</ref> Seasonal modifications of reproductive functions <ref>Meriggiola, M.C., Noonan, E.A., Paulsen, C.A. and Bremner, W.J. (1996) Annual patterns of luteinizing hormone, follicle stimulating hormone, testosterone and inhibin in normal men. Hum. Reprod., 11, 248–252.</ref> and semen parameters <ref>Levine, R.J., Brown, M.H., Bell, M. et al. (1992) Air-conditioned environments do not prevent deterioration of human semen quality during summer. Fertil. Steril., 57, 1075–1083.</ref> are documented in human males. Recent trends noted a decline in relation of seasonal variation and human conception rhythm. The increased industrialization leading to increase in people being shielded from both photoperiod (by indoor work) and temperature (by heating and air conditioning) might be the reason behind this.<ref>Till Roenneberg, Jürgen Aschoff, Annual Rhythm of Human Reproduction: II. Environmental Correlations, J Biol Rhythms September 1990 vol. 5 no. 3 217-239</ref>

==== Cause of infertility ====

==== Cause of infertility ====