Any kind of collective identification requires some type of self-mutilation. The constraints of collective identity do not allow enough space for the incredible variety of human existence. That is why in order to belong we need to mutilate ourselves intellectually, spiritually, and often physically to fit into the mold and signal that we are part of the group. Female identity requires an even bigger amount of self-mutilation than other collective identifications.
I'm dropping out of grad school/leaving my job to follow my boyfriend. So what if I won't have a life and career of my own? At least, we will be together.
So what if I don't have an orgasm with this man? We get along well, and that's what matters.
I'm not going to have an elective C-section and avoid a long and painful labor. So what if my vagina gets torn to shreds in the process? It's not like I use it much anyways.
Who cares that my nipples are bleeding and I'm in pain? I'll keep breastfeeding until I drop dead because it's my duty.
I'm going to take on all kinds of boring and unfulfilling responsibilities at work. So what if they get in the way of my research and don't let me get tenure and promotion? Somebody's got to do it, and I'm always happy to be helpful.
So what if I don't feel like having sex right now? I don't want to upset my boyfriend or hurt his feelings. I'm just going to do it and hope it's over fast.
I come home from work dead tired and immediately start cleaning, doing the laundry, and cooking. Of course, I'm exhausted but if I don't do it no one will.
Sacrificing your interests, making your body serve everybody else's purposes except your own, suffering, accepting pain as your natural state of being - these are some of the most popular ways of signalling your belonging to female identity.
If anybody has their own version of why this happens, feel free to tell me in the comments. Then, I will propose my theory of the reasons behind the sacrificial womanhood.