Skip to main content Accessibility help

Sex-dependent toxoplasmosis-associated differences in testosterone concentration in humans

  • J. FLEGR (a1), J. LINDOVÁ (a1) (a2) and P. KODYM (a3)


Several lines of indirect evidence suggest that subjects with latent infection of the coccidian parasite Toxoplasma gondii have a higher concentration of testosterone than uninfected controls. Here, we searched for direct evidence of latent toxoplasmosis-associated differences in testosterone concentration among a population of 174 female and 91 male students screened for Toxoplasma infection. We have found Toxoplasma-infected men to have a higher concentration of testosterone and Toxoplasma-infected women to have a lower concentration of testosterone than Toxoplasma-free controls. The opposite direction of the testosterone shift in men compared to women can explain the observed gender specificity of behavioural shifts in Toxoplasma-infected subjects.


Corresponding author

*Corresponding author: Department of Parasitology, Faculty of Science, Charles University, Viničná 7, CZ-128 44 Praha 2, Czech Republic. Tel: +420 221951821. Fax: +420 224919704. E-mail:


Hide All
Barnard, C. J. and Behnke, J. M. (1990). Parasitism and Host Behaviour. 1st Edn. Taylor and Francis, New York.
Brems, C. and Johnson, M. E. (1989). Problem-solving appraisal and coping style – the influence of sex-role orientation and gender. Journal of Psychology 123, 187194.
Brown, W. M., Hines, M., Fane, B. A. and Breedlove, S. M. (2002). Masculinized finger length patterns in human males and females with congenital adrenal hyperplasia. Hormones and Behavior 42, 380386.
Carver, C. S., Scheier, M. F. and Weintraub, J. K. (1989). Assessing coping strategies – a theoretically based approach. Journal of Personality and Social Psychology 56, 267283.
Dawkins, R. (1982). The Extended Phenotype, the Gene as the Unit of Selection. 1st Edn. W.H. Freeman, Oxford.
Drop, S. L. S., De Waal, W. J. and Keizer-Schrama, S. M. P. F. (1998). Sex steroid treatment of constitutionally tall stature. Endocrine Reviews 19, 540558.
Dominguez, J. M. and Hull, E. M. (2005). Dopamine, the medial preoptic area, and male sexual behavior. Physiology and Behavior 86, 356368.
Flegr, J. (2007). Effects of Toxoplasma on human behavior. Schizophrenia Bulletin 33, 757760.
Flegr, J., Hruskova, M., Hodny, Z., Novotna, M. and Hanusova, J. (2005). Body height, body mass index, waist-hip ratio, fluctuating asymmetry and second to fourth digit ratio in subjects with latent toxoplasmosis. Parasitology 130, 621628.
Flegr, J., Kodym, P. and Tolarova, V. (2000). Correlation of duration of latent Toxoplasma gondii infection with personality changes in women. Biological Psychology 53, 5768.
Flegr, J., Zitkova, S., Kodym, P. and Frynta, D. (1996). Induction of changes in human behaviour by the parasitic protozoan Toxoplasma gondii. Parasitology 113, 4954.
Hodkova, H., Kolbekova, P., Skallova, A., Lindová, J. and Flegr, J. (2007). Higher perceived dominance in Toxoplasma infected men – the new evidence for role of increased level of testosterone in toxoplasmosis-associated changes in human behavior. Neuroendocrinology Letters 28, 101105.
Hull, E. M., Muschamp, J. W. and Sato, S. (2004). Dopamine and serotonin: influences on male sexual behavior. Physiology and Behavior 83, 291307.
James, W. H. (1986). Hormonal control of sex ratio. Journal of Theoretical Biology 118, 427441.
James, W. H. (1996). Evidence that mammalian sex ratios at birth are partially controlled by parental hormone levels at the time of conception. Journal of Theoretical Biology 180, 271286.
Kaňková, Š., Šulc, J., Nouzová, K., Fajfrlík, K., Frynta, D. and Flegr, J. (2007). Women infected with parasite Toxoplasma have more sons. Naturwissenschaften 94, 122127.
Kodym, P., Machala, L., Rohacova, H., Sirocka, B. and Maly, M. (2007). Evaluation of a commercial IgE ELISA in comparison with IgA and IgM ELISAs, IgG avidity assay and complement fixation for the diagnosis of acute toxoplasmosis. Clinical Microbiology and Infection 13, 4047.
Lindová, J., Novotná, M., Havliček, J., Jozífková, E., Skallová, A., Kolbeková, P., Hodný, Z., Kodym, P. and Flegr, J. (2006). Gender differences in behavioural changes induced by latent toxoplasmosis. International Journal for Parasitology 36, 14851492.
Lutchmaya, S., Baron-Cohen, S., Raggatt, P., Knickmeyer, R. and Manning, J. T. (2004). 2nd to 4th digit ratios, fetal testosterone and estradiol. Early Human Development 77, 2328.
Neave, N., Laing, S., Fink, B. and Manning, J. T. (2003). Second to fourth digit ratio, testosterone and perceived male dominance. Proceedings of the Royal Society of London, B 270, 21672172.
Okten, A., Kalyoncu, M. and Yaris, N. (2002). The ratio of second- and fourth-digit lengths and congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Early Human Development 70, 4754.
Pokorný, J., Fruhbauer, Z., Polednakova, S., Sykora, J., Zastera, M. and Fialova, D. (1989). Stanoveni antitoxoplasmickych protilatek IgG netodou ELISA (Assessment of antitoxoplasmatic IgG antibodies with the ELISA method). Ceskoslovenska Epidemiologie 38, 355361.
Roberts, C. W., Walker, W. and Alexander, J. (2001). Sex-associated hormones and immunity to protozoan parasites. Clinical Microbiology Reviews 14, 476488.
Schuster, J. P. and Schaub, G. A. (2001). Experimental Chagas disease: the influence of sex and psychoneuroimmunological factors. Parasitology Research 87, 9941000.
Szczypka, M. S., Zhou, Q. Y. and Palmiter, R. D. (1998). Dopamine-stimulated sexual behavior is testosterone dependent mice. Behavioral Neuroscience 112, 12291235.
Tenter, A. M., Heckeroth, A. R. and Weiss, L. M. (2000). Toxoplasma gondii: from animals to humans. International Journal for Parasitology 30, 12171258.
Warren, J. and Sabin, A. B. (1942). The complement fixation reaction in toxoplasmic infection. Proceedings of the Society for Experimental Biology and Medicine 51, 1116.
Webster, J. P. (2001). Rats, cats, people and parasites: the impact of latent toxoplasmosis on behaviour. Microbes and Infection 3, 10371045.


Sex-dependent toxoplasmosis-associated differences in testosterone concentration in humans

  • J. FLEGR (a1), J. LINDOVÁ (a1) (a2) and P. KODYM (a3)


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed