Estrogen Resistance or Estrogen Insensitivity Syndrome (EIS) is an extremely rare intersex variation only known to affect six individuals so far. Individuals with estrogen resistance have defective estrogen receptors (ER) that cannot achieve their goal. This variation effects both CTM and CTF individuals alike.
One reported AMAB individual with EIS was abnormally tall, as estrogens were unable to act close to the epiphyseal line, and put them at risk for osteoporosis and sterile, which suggests that in biological humans, estrogens are necessary for reproduction. One with this variation cannot impregnate anyone, as they are infertile.
CTM individuals with this variation are shown to be infertile with low sperm count, a micropenis or cryptorchidism, unusual and low hair growth, and underdeveloped organs.
CTF individuals with this variation are shown to have little to no breast development, amenorrhea, increased acne, ovarian cysts, ovaries with an increased or decreased size, a small uterus, hyperandrogenism, low bone mass, and small hips.
It is important to note that not all the symptoms listed in this page are guaranteed to occur in someone with this variation, as someone may only experience one or several of these symptoms, yet still hold the variation.
The flag was coined by Mod Hermy through Pride-color-schemes Tumblr account on June 15th of 2017. It is made to represent an orchid, as orchids are often used as a symbol for intersex individuals.
The first case of this variation was in 1994, in which a CTM individual was discovered to have biological development delays. Upon medical examination, the variation was discovered, making him the first ever case to be reported.
Within one of the cases of this variation, two sisters and one brother were all born with EIS. It was concluded upon study that the reason behind this was from high plasma within the 17β-estradiol gene. This was due to a defect in forming within the womb, because of the incestual relationship of their parents, who were first cousins.
This does not mean that incestual relations is the reason for this variation, but rather means that it can intensify the likelihood of it in development.