Adhesions (the body's process for treating significant trauma) in the female reproductive system can result in infertility. A significant trauma to ANYWHERE around the female pelvis (including the hip or the tail bone) can result in this.

"Adhesions (or scarring) are a leading cause of female infertility and the primary cause of blocked fallopian tubes. They form as a natural part of healing as the body responds to tissue insult.

Adhesions can form anywhere in the body. When they form within the delicate structures of the female reproductive tract, they tend to glue down structures that are designed to move freely.

Adhesion formation is the first step in the body’s healing process. Adhesions surround areas as they heal, with strong glue-like fibres that create tiny but powerful bonds. These bonds may be shaped like curtains, ropes, woven patterns, or a combination of these.

Adhesions or scarring anywhere in the pelvis can cause pain or infertility.

There are four main causes of the adhesions that cause infertility:

Infection (e.g. vaginal, bladder, yeast)

Inflammation (e.g. endometriosis, chlamydia, PID)

Surgery (any surgery to the pelvis, abdomen, hip or back)

Trauma (fall onto tailbone, back or hip, abuse)

It is an unfortunate fact that once adhesions form, they generally remain in the body for a lifetime. Adhesions may occur in pain-sensitive structures, or they may glue down reproductive structures without causing discomfort. Thus, any woman who has experienced any of the four causes listed above may have adhesions that cause infertility, whether or not she experiences pain."

Besides, to actually be punched in the vulva would look more like a Tekken Jin up-punch juggle than the punch depicted in the gif there.

tl;dr Redditors have so little understanding of basic anatomy.