Qe prej vitit 1990 nivelet e mosshtimit te popullsisë ne bote kane mbetur relativisht te pandryshuara. Ky është konkluzioni ne te cilin ka arritur Organizata Botërore e Shendetesise pas nje studimi gati 20-vjeçar. Punonjësja e sektorit te statistikave ne OBSH, Gretchen Stevens e cila drejtoi studimin lidhur me nivelet e rënies se lindjeve sqaron: U analizuan qindra familje ne 190 vende te botes ne periudhën 1990-2010. Ky është ne fakt studimi i pare qe shqyrton nivelet e mosshtimit te popullsisë ne vende te ndryshme. Dhe sipas statistikave te para, njerëzit kane shtuar përdorimin e kontraceptiveve per te parandaluar shtatzënitë. E vetmja zone qe bënte përjashtim ishte Afrika nensahariane. Zonja Stevens thotë se ne Afriken nensahariane nje prej arsyeve kryesore te rënies se lindjeve ka te beje me infeksionet e transmetuara nga marrëdhëniet seksuale. Edhe vete studiuesit kane mbetur te habitur nga rezultatet përfundimtare.
Since 1990 mosshtimit levels of the world's population have remained relatively unchanged. This is the conclusion we arrived at the World Health Organization after a nearly 20-year study. WHO statistics sector worker, Gretchen Stevens who led the study associated with declining levels of fertility explains: were analyzed hundreds of families in 190 countries around the world in the period 1990-2010. This is actually the first study that examines mosshtimit levels of the population in different countries. And according to the statistics before, humans have increased the use of contraceptives to prevent pregnancies. The only area that was made ??except sub-Saharan Africa. Ms Stevens says that in sub-Saharan Africa one of the main reasons for the fall of the birth has to do with infections transmitted by sexual relations. Even the researchers have remained puzzled by the final results.
