青春期前的閹割
在青春期之前，用外科手術切除睾丸，既閹割，會阻止男孩性發育。他不會有變聲過程，其性器官維持幼稚狀態，而且沒有生育能力。

去勢者和太監
幾個世紀前，儘管有不同的理由，歐洲和亞洲都有閹割男孩的習俗。在歐洲，閹割男孩是為了訓練他們做歌劇明星（被稱為去勢者），既唱很高音階和響亮聲音的男歌手。有些歌手因此而發了財和出了名，甚至像漢德爾（Handel）和莫札特（Mozart）這樣的偉大作曲家也為他們作過曲。在亞洲，閹割男孩是為了讓他們作閨房看守（被稱為太監）。太監留在婦女的身邊能夠讓人放心，因為他們不能讓婦女懷孕了。

What are the effects of castration on sexual behavior?

Castration before puberty
Before puberty, castration, i.e the surgical removal of the testicles, prevents a boy's sexual maturation. He does not experience a voice change, his sex organs remain underdeveloped, and he remains infertile.

Castrati and eunuchs
In previous centuries, both Europe and Asia had a custom of castrating some young boys, although for different reasons: In Europe the boys were castrated in order to train them as opera stars (so-called castrati), i.e. male singers with very high and very strong voices. Some of them became very rich and famous, and the greatest composers like Handel and Mozart wrote operas for them. In Asia, boys were castrated in order to make them harem guards (so-called eunuchs). They could “safely” be left in the company of women, because they could not impregnate them.

從左至右：義大利：義大利被閹割的男歌手Farinelli（Carlo Broschi，1705-1782）曾經過著童話般的生活，他先是在歐洲劇院唱歌，後來在馬德里的西班牙皇家宮廷唱歌。土耳其：土耳其帝國也雇傭被閹割者作閨房守衛。此出顯示的是“白人太監主管”。中國：正如這幅早期的照片所顯示的那樣，皇宮的太監們不僅被切除了睾丸，而且連陰莖也被切除了。 From the left: Italy: The Italian castrato Farinelli (Carlo Broschi 1705-1782) led a fairy-tale life, first on European opera stages and then at the Spanish royal court in Madrid. Turkey: The Ottoman Empire also employed castrated men as harem guards. Shown here is the “Chief of the White Eunuchs”. China: As this early photograph shows, the eunuchs of the imperial court usually had not only their testicles cut off but also the penis.