Image content influences men's semen quality

There is increasing evidence from non-human animals that males adjust their ejaculate expenditure according to the risk of sperm competition. In this study we show that, after controlling for lifestyle factors known to influence semen quality, human males viewing images depicting sperm competition had a higher percentage of motile sperm in their ejaculates. Many lifestyle variables were confirmed to influence semen quality, including the recent suggestion that storage of mobile phones close to the testes can decrease semen quality.

[1]  A. Pilastro,et al.  Individual adjustment of sperm expenditure accords with sperm competition theory , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[2]  T. Bakker,et al.  Body size of virtual rivals affects ejaculate size in sticklebacks , 2004 .

[3]  R. Aitken,et al.  Impact of radio frequency electromagnetic radiation on DNA integrity in the male germline. , 2005, International journal of andrology.

[4]  Suleyman Dasdag,et al.  Whole body exposure of rats to microwaves emitted from a cell phone does not affect the testes , 2003, Bioelectromagnetics.

[5]  R. Aitken,et al.  Seeds of concern , 2004, Nature.

[6]  R. Burslem,et al.  Unexplained infertility. , 1986, British medical journal.

[7]  G. Parker,et al.  Sperm competition games: individual assessment of sperm competition intensity by group spawners , 1996, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[8]  G. Parker,et al.  Sperm competition games: a prospective analysis of risk assessment , 1997, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[9]  Y. Mio,et al.  Influence of sexual stimulation on sperm parameters in semen samples collected via masturbation from normozoospermic men or cryptozoospermic men participating in an assisted reproduction programme , 2000, Andrologia.

[10]  P. Hemsworth,et al.  The effect of sexual stimulation on the sperm output of the domestic boar , 1979 .

[11]  R. Montgomerie,et al.  Sperm swimming speed and energetics vary with sperm competition risk in bluegill (Lepomis macrochirus) , 2004, Behavioral Ecology and Sociobiology.

[12]  M. Gage,et al.  Prudent sperm allocation in Norway rats, Rattus norvegicus: a mammalian model of adaptive ejaculate adjustment , 2004, Animal Behaviour.

[13]  N. Pound.  Male interest in visual cues of sperm competition risk , 2002 .

[14]  E. Price,et al.  The effects of sexual stimulation on the sexual performance of Hereford bulls. , 1984, Journal of Animal Science.

[15]  A. Lenzi,et al.  Effects of prolonged autovehicle driving on male reproduction function: a study among taxi drivers. , 1996, American journal of industrial medicine.

[16]  M. Ferkin,et al.  Male mammals respond to a risk of sperm competition conveyed by odours of conspecific males , 2004, Nature.

[17]  T. Vladić.  Sperm quality in the alternative reproductive tactics of Atlantic salmon: the importance of the loaded raffle mechanism , 2001, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[18]  R. Sharpe,et al.  Environment, lifestyle and infertility--an inter-generational issue. , 2002, Nature cell biology.

[19]  T. Burke,et al.  Sperm mobility determines the outcome of sperm competition in the domestic fowl , 1999, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[20]  G. Parker,et al.  Sperm competition, male prudence and sperm-limited females , 2002 .

[21]  T. Birkhead,et al.  Sophisticated sperm allocation in male fowl , 2003, Nature.

[22]  W. Hänggi,et al.  Semen quality of male smokers and nonsmokers in infertile couples. , 2003, Fertility and sterility.