Για να είμεθα πιο ορθοί και ακριβείς, ίσως το θέμα να είναι το μέγεθος per se αλλά το γεγονός ότι η μέση γυναίκα, χωρίς να έχει κάποιο ειδικό θέμα, αισθάνεται σχετικό "κορεσμό" (και άρα ανάγκη επίσκεψης στην τουαλέτα για ούρηση) διαθέτωντας λιγότερη ποσότητα ούρων στην κύστη, απ' ότι ο μέσος άνδρας, οπότε τα voids είναι συχνότερα. Γιατί τώρα μπορεί να συμβαίνει αυτό; Enjoy:"In females, the bladder sits inferior to the uterus and anterior to the vagina; thus its maximum capacity is lower than in males".(Απ' την wiki)--(...) We're not denying that most of us need to use the bathroom more frequently than our partner, but this has more to do with the position of our bladder than its size, says Barnes-Svarney. A woman's bladder is supported by the front wall of the uterus and vagina, she says, and this wall weakens with age and childbirth, while the way a woman carries excess fat also adds uncomfortable pressure. Men's bladders, on the other hand, are freer to expand (...)(Απ'το oprah.com)--"Functional bladder capacity is the urine volume that triggers micturition sensation. And, yes, there are slight differences between men and women:Fitzgerald, Stablein, and Brubaker (2002) evaluated voiding diaries in 300 women with differing racial and ethnic backgrounds, and reported that the median voided volume was 330 ml. Latini, Mueller, Lux, Fitzgerald, and Kreder (2004) analyzed multiple variables from voiding diaries in 284 men without bothersome lower urinary tract symptoms and found that the median voided volume was 382 ml. Van Doorn and associates (2011) evaluated voiding parameters in 1688 Dutch men and found a similar mean voided volume in adult men of 400 ml."https://skeptics.stackexchange.com/questions/22303/do-women-have-smaller-bladders-than-men+http://www.jurology.com/article/S0022-5347(05)60521-6/fulltext--"1. Bladder size tends to follow body size  so a male and female of equal body size might well have similar sized bladders.2. But males have better, larger, and stronger urethral sphincters for stopping urine flow (this is known from anatomy and from measurements of urethral squeezing pressure).3.Therefore, on average males can hold their urine to higher pressures and therefore to higher volumes that females (this means more urine and longer holding times).4. As to room in the lower abdominal cavity -- well contrary to statements on this string -- males have MORE room down there as they do NOT have a uterus laying right on top of their bladder like females do".http://beamsandstruts.com/bits-a-pieces/item/928-pee--Αλλά και:"In our study, it was noted that male students had a greater capacity to hold urine, but this urine holding capacity cannot be attributed to increased BMI. (...)It is concluded that the current study suggested that bladder capacity itself is not affected by gender or body mass index. However, there is an effect of unfavorable circumstances on urine holding capacity by bladder (accommodation behavior) under voluntary control. Moreover, despite of the fact that bladder size is not affected by gender, males had an urge and comp-laint of abdominal pain and tenderness due to filling of bladder much later than females. This can be attributed to anatomical difference between male and female’s smooth muscle of bladder".https://www.google.gr/url?sa=t&source=web&rct=j&url=https://pdfs.semanticscholar.org/6fd2/97249082aa76501ca6b97c64192443ba6272.pdf&ved=2ahUKEwitmcKPyZbaAhUmsaQKHTAkC2EQFjAFegQIAhAB&usg=AOvVaw0blMPGjkYfslkpR-OpGwf8