A. G. Andersen, T. K. Jensen, E. Carlsen, N. Jørgensen, A. M. Andersson et al., High frequency of sub-optimal semen quality in an unselected population of young men, Hum Reprod, vol.15, pp.366-372, 2000.

J. Y. Bahk, J. H. Jung, J. Lm-&-min, and S. K. , Cut-off value of testes volume in young adults and correlation among testes volume, body mass index, hormonal level, and seminal profiles, Urology, vol.75, pp.1318-1323, 2010.

K. A. Boisen, M. Kaleva, K. M. Main, H. E. Virtanen, A. Haavisto et al., Difference in prevalence of congenital cryptorchidism in infants between two Nordic countries, Lancet, vol.363, pp.1264-1269, 2004.

J. Bonde, E. Ernst, T. K. Jensen, N. Hjollund, H. Kolstad et al., Relation between semen quality and fertility: a population-based study of 430 first-pregnancy planners, Lancet, vol.352, pp.1172-1177, 1998.

E. Carlsen, A. Giwercman, N. Keiding, and N. E. Skakkebaek, Evidence for decreasing quality of semen during past 50 years, BMJ, vol.305, pp.609-613, 1992.

T. G. Cooper, E. Noonan, S. Von-eckardstein, J. Auger, H. Baker et al., World Health Organization reference values for human semen characteristics* ?, Hum Reprod Update, vol.16, pp.231-245, 2010.

J. Damsgaard, U. N. Joensen, E. Carlsen, J. Erenpreiss, B. Jensen et al., Platinum Priority -Andrology Varicocele Is Associated with Impaired Semen Quality and Reproductive Hormone Levels: A Study of 7035 Healthy Young Men from Six European Countries, pp.0-1, 2016.

M. Deonandan-r-&-jaleel, Global decline in semen quality: ignoring the developing world introduces selection bias, Int J Gen Med, vol.5, pp.303-306, 2012.

R. D. Dubin-l-&-amelar, Varicocele size and results of varicocelectomy in selected subfertile men with varicocele, Fertil Steril, vol.21, pp.606-609, 1970.

J. Erenpreiss, M. Punab, B. Zilaitiene, S. Hlevicka, P. Zayakin et al., Semen quality of young men from the general population in Baltic countries, Hum Reprod, vol.32, pp.1334-1340, 2017.

M. F. Fernandez, I. Duran, N. Olea, C. Avivar, M. Vierula et al., Semen quality and reproductive hormone levels in men from Southern Spain, Int J Androl, vol.35, pp.1-10, 2012.

S. M. Garn, Growth at adolescence. By J. M. Tanner. Pp. vii + 212, vol.14, pp.120-122, 1955.

D. S. Guzick, J. W. Overstreet, P. Factor-litvak, C. K. Brazil, S. T. Nakajima et al., Sperm morphology, motility, and concentration in fertile and infertile men, N Engl J Med, vol.345, pp.1388-1393, 2001.

R. J. Hart, D. A. Doherty, R. I. Mclachlan, M. L. Walls, J. A. Keelan et al., Testicular function in a birth cohort of young men, Hum Reprod, vol.30, p.244, 2015.

R. Hauser, G. Chen, and Z. , Does the potential for selection bias in semen quality studies depend on study design? Experience from a study conducted within an infertility clinic, Hum Reprod, vol.20, pp.2579-2583, 2005.

T. Iwamoto, S. Nozawa, M. N. Mieno, K. Yamakawa, K. Baba et al., Semen quality of 1559 young men from four cities in Japan: a cross-sectional population-based study, BMJ Open, vol.3, p.2222, 2013.

M. S. Jensen, L. M. Mabeck, G. Toft, A. M. Thulstrup, and J. P. Bonde, Lower sperm counts following prenatal tobacco exposure, Hum Reprod, vol.20, pp.2559-2566, 2005.

N. Jorgensen, Regional differences in semen quality in Europe, Hum Reprod, vol.16, pp.1012-1019, 2001.

N. Jorgensen, East-West gradient in semen quality in the Nordic-Baltic area: a study of men from the general population in Denmark, Hum Reprod, vol.17, pp.2199-2208, 2002.

N. Jørgensen, M. Vierula, R. Jacobsen, E. Pukkala, A. Perheentupa et al., Recent adverse trends in semen quality and testis cancer incidence among Finnish men, Int J Androl, vol.34, pp.37-48, 2011.

H. Kim and M. Goldstein, A new clinical grading system for varicocele, Fertil Steril, vol.90, p.467, 2008.

L. Moal, J. Rolland, M. Goria, S. Wagner, V. et al., Semen quality trends in French regions are consistent with a global change in environmental exposure, Reproduction, vol.147, pp.567-574, 2014.
URL : https://hal.archives-ouvertes.fr/hal-01129835

H. Levine, N. Jørgensen, A. Martino-andrade, J. Mendiola, D. Weksler-derri et al., Temporal trends in sperm count: a systematic review and meta-regression analysis, Hum Reprod Update, vol.23, pp.646-659, 2017.

M. Lorez, A. Bordoni, C. Bouchardy, J. L. Bulliard, B. Camey et al., Evaluation of completeness of case ascertainment in Swiss cancer registration, Eur J Cancer Prev, vol.26, pp.139-146, 2017.

W. K. Ly, C. Gapany, P. Frey, F. Cachat, F. Gudinchet et al., Management of cryptorchidism in children: guidelines, 2008.

J. Mendiola, R. W. Stahlhut, N. Jørgensen, F. Liu, and S. H. Swan, Shorter anogenital distance predicts poorer semen quality in young men in Rochester, Environ Health Perspect, vol.119, pp.958-963, 2011.

J. Mendiola, N. Jørgensen, M. Inguez-alarc-on, L. Sarabia-cos, L. et al., Sperm counts may have declined in young university students in Southern Spain, Andrology, vol.1, pp.408-413, 2013.

R. Menkveld, F. S. Stander, T. J. Kotze, T. F. Kruger, and J. A. Van-zyl, The evaluation of morphological characteristics of human spermatozoa according to stricter criteria, Hum Reprod, vol.5, pp.586-592, 1990.

A. Muller, L. Rochebrochard, E. , D. Labb-e-decl-eves, C. Jouannet et al., Selection bias in semen studies due to self-selection of volunteers, Hum Reprod, vol.19, pp.2838-2844, 2004.
URL : https://hal.archives-ouvertes.fr/inserm-00086303

, Niveau de formation de la population r esidante permanente selon l'âge et le sexe -1999-2017 | Tableau, OFS. Pratiques linguistiques en Suisse -Premiers r esultats de l, 1992.

U. Paasch, A. Salzbrunn, H. J. Glander, K. Plambeck, H. Salzbrunn et al., Semen quality in sub-fertile range for a significant proportion of young men from the general German population: a co-ordinated, controlled study of 791 men from Hamburg and Leipzig, Int J Androl, vol.31, pp.93-102, 2008.

G. Palermo, H. Joris, P. Devroey, and A. C. Van-steirteghem, Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte, Lancet, vol.340, pp.17-18, 1992.

A. Perheentupa, S. Sadov, R. Virtanen, H. E. Rodprasert, W. Vierula et al., Semen quality improves marginally during young adulthood: a longitudinal followup study, Hum Reprod, vol.31, pp.502-510, 2016.

L. Priskorn, L. Nordkap, A. K. Bang, M. Krause, S. A. Holmboe et al., Average sperm count remains unchanged despite reduction in maternal smoking: results from a large cross-sectional study with annual investigations over 21 years, Hum Reprod, vol.333, pp.998-1008, 2018.

M. Punab, B. Zilaitiene, N. Jørgensen, A. Horte, V. Matulevicius et al., Regional differences in semen qualities in the Baltic region, Int J Androl, vol.25, pp.243-252, 2002.

C. H. Ramlau-hansen, A. M. Thulstrup, L. Storgaard, G. Toft, J. Olsen et al., Is prenatal exposure to tobacco smoking a cause of poor semen quality? A follow-up study, Am J Epidemiol, vol.165, pp.1372-1379, 2007.

T. L. Ravnborg, T. K. Jensen, A. Andersson, J. Toppari, S. Ne-&-jorgensen et al., Prenatal and adult exposures to smoking are associated with adverse effects on reproductive hormones, semen quality, final height and body mass index, Hum Reprod, vol.26, pp.1000-1011, 2011.

O. Reinberg, Varicoc ele de l'enfant et de l'adolescent -Revue M edicale Suisse, 2007.

J. Richthoff, L. Rylander, L. Hagmar, J. Malm, and A. Giwercman, Higher sperm counts in Southern Sweden compared with Denmark, Hum Reprod, vol.17, pp.2468-2473, 2002.

W. Rodprasert, H. E. Virtanen, S. Sadov, A. Perheentupa, N. E. Skakkebaek et al., An update on semen quality among young Finnish men and comparison with Danish data, Andrology, vol.7, pp.15-23, 2019.

H. Sakamoto, K. Saito, Y. Ogawa, and H. Yoshida, Testicular volume measurements using prader orchidometer versus ultrasonography in patients with infertility, Urology, vol.69, pp.158-162, 2007.

A. Al-salim, P. J. Murchison, R. A. , E. Ra-&-hargreave, and T. B. , Evaluation of testicular volume by three orchidometers compared with ultrasonographic measurements, Br J Urol, vol.76, pp.632-635, 1995.

T. Serrano, C. Chevrier, L. Multigner, S. Cordier, and B. Jegou, International geographic correlation study of the prevalence of disorders of male reproductive health, Hum Reprod, vol.28, pp.1974-1986, 2013.
URL : https://hal.archives-ouvertes.fr/inserm-00863412

N. E. Skakkebaek and K. M. Rajpert-de-meyts-e-&-main, Testicular dysgenesis syndrome: an increasingly common developmental disorder with environmental aspects, Hum Reprod, vol.16, pp.972-978, 2001.

N. E. Skakkebaek, E. Rajpert-de-meyts, B. Louis, G. M. Toppari, J. Andersson et al., Male reproductive disorders and fertility trends: influences of environment and genetic susceptibility, Physiol Rev, vol.96, pp.55-97, 2016.

R. Slama, F. Eustache, B. Ducot, T. K. Jensen, N. Jørgensen et al., Time to pregnancy and semen parameters: a cross-sectional study among fertile couples from four European cities, Hum Reprod, vol.17, pp.503-515, 2002.

K. Staub, . Fj, U. Woitek, and C. Pfister, BMI distribution/social stratification in Swiss conscripts from 1875 to present, Eur J Clin Nutr, vol.64, pp.335-340, 2010.

L. Storgaard, J. P. Bonde, E. Ernst, M. Spanô, C. Y. Andersen et al., Does smoking during pregnancy affect sons' sperm counts?, Epidemiology, vol.14, pp.278-286, 2003.

S. H. Swan, C. Brazil, E. Z. Drobnis, F. Liu, R. L. Kruse et al., Study For Future Families Research Group SFFFR (2003) Geographic differences in semen quality of fertile U.S. males, Environ Health Perspect, vol.111, pp.414-420

I. Tsarev, V. Gagonin, A. Giwercman, and J. Erenpreiss, Sperm concentration in Latvian military conscripts as compared with other countries in the Nordic-Baltic area, Int J Androl, vol.28, pp.208-214, 2005.

V. Goebel and F. K. , Areas with urban character 2012, 2014.