Morris Syndrome: Characteristics, Causes and Reproductive Options

By (embryologist) and (babygest staff).
Last Update: 09/10/2019

Morris syndrome is a genetic disorder characterized by the birth of individuals with XY sex chromosomes, that is, male sex, and yet their development and physical characteristics are those of a woman.

For this reason, Morris syndrome might be considered a type of male pseudohermaphroditism.

This pathology is also called Androgen Insensitivity Syndrome(AIS), since these people lack receptors to assimilate male sex hormones and, therefore, their sexual development is characteristic of that of women.

What is Morris syndrome?

First, it is very important to note that people born with Morris syndrome are considered women, although their karyotype is 46,XY.

In other words, the genotype of people with Morris syndrome is male, while its phenotype is female.

Their sexual characteristics and physical appearance are those of a woman, but their internal reproductive system lacks uterus and ovaries. Normally, these women are diagnosed with Morris syndrome when they reach puberty and do not have monthly bleeding.

The male pseudohermaphroditism condition - which is characteristic of Morris syndrome- is due to the fact that these women have elevated testosterone levels in their blood as if they were men, but they are not capable of assimilating it and their body follows a female sexual development.


The cause of Morris syndrome is a genetic mutation in the AR gene (androgen receptor) located on the X chromosome.

Due to this genetic alteration, there is no formation of the androgen receptors necessary to assimilate testosterone, so the situation of resistance to androgens appears.

Testosterone is the male sex hormone responsible for the appearance of secondary sexual characteristics in men, such as the development of musculature, the appearance of the beard, the change of voice, maturation of the testicles, etc.

The AR gene mutation may be inherited from the mother or may appear de novo in a newly formed embryo. In the following section, we are going to detail these two situations:

AIS through maternal inheritance
is the most common cause of Morris Syndrome. The mother carries the mutation on one of her X chromosomes, but the disease does not show up because it is recessive (two altered copies of the gene are needed for it to show up). This mother can have XX daughters without any alterations or carriers, but if she has an XY son, there is a risk of Morris syndrome.
AIS through de novo mutation
a spontaneous mutation occurs in the egg after completion of its maturation or in the embryo during its early stages of development.

Degrees of male pseudohermaphroditism

The severity of this pathology depends on the level of androgen receptor deficiency, that is, the fewer androgen receptors a woman has, the greater the resistance to androgens.

With this in mind, the following types of androgen insensitivity may occur:

Incomplete AIS
the woman may have some masculine traits, as she would assimilate a small proportion of testosterone. For example, undescended testicles, clitoromegaly or micropenis, partial closure of the vagina, etc.
Complete AIS
resistance to androgens is complete and therefore the phenotypic characteristics and the external genitalia are completely female. This is the condition that would correspond to Morris syndrome.

Complete AIS can also be called complete testicular feminization, since there is no development of the penis or other male body organs.

Symptoms and characteristics

Androgen insensitivity syndrome has particular characteristics. As we have already mentioned, the development of the affected person is female, as well as the external reproductive system that is hormone-dependent. Therefore, these women have normal vagina, vulva, and breasts.

However, as they have their own male chromosome endowment (XY), these women have neither uterus nor ovaries. What they do have are testicles that can remain inside, since the formation of the testicles is dependent on the Y chromosome that is present in these women.

Symptoms of Morris syndrome do not appear until puberty, when the girl waits for her first menstruation called menarche. Since these women don't have a uterus, they won't be able to have periods either.

Other symptoms of androgen insensitivity syndrome include the following:

  • Short vagina with blind termination
  • Missing uterus, fallopian tubes and ovaries
  • Smaller vulvar lips
  • Undescended atrophied testicles remaining in the inguinal region or abdomen
  • Tall stature and narrower hip
  • Scarce armpit and pubic hair
  • Decreased bone density

Having children with Morris syndrome

Obviously, women with Morris syndrome cannot become pregnant or have biological children, as their internal reproductive system is absent and they do not have the most important reproductive organs, which are uterus and ovaries.

Therefore, these women are infertile and only have two options to become mothers:

In the US both single adults or married couples can be eligible to adopt which depends, however, on every States’ law. It is also possible to adopt abroad in those destinations that have adoption agreements with the US.
is an assisted reproduction technique in which a woman (the surrogate mother or also referred to as gestational carrier) agrees to maintain the pregnancy and give birth to the baby of another woman who suffers from sterility or who, for medical reasons, has the pregnancy contraindicated.

Opting for the second option, women with AIS will also have to resort to egg donors to carry out the in vitro fertilization (IVF) process and transfer the embryo to the surrogate mother.

FAQs from users

Can Morris syndrome be prevented?

By Zaira Salvador (embryologist).

Yes, since it is a genetic alteration linked to the X chromosome, Morris syndrome could be avoided by making a preimplantation genetic diagnosis (PGD) of the embryos during IVF treatment.

However, in order to perform PGD, the woman would have to know that she is a carrier of Morris syndrome in order to carry out an informative study and locate the specific mutation of the disease.

Is there any treatment for Morris Syndrome?

By Zaira Salvador (embryologist).

Morris syndrome cannot be cured because it is an irreversible genetic alteration. However, there are some treatments to try to compensate some of the deficiencies of these women and they can lead a life as normal as possible.

For example, a surgical intervention of the vagina or vaginal dilators in cases of very narrow vagina so that the woman can have sex normally. Calcium and vitamin D supplements are also needed to treat her lack of bone density. Another surgical intervention that may be necessary is the removal of atrophied testicles by gonadectomy to prevent the formation of tumors such as gonadoblastoma.

How is Androgene Insensitivity Syndrome diagnosed?

By Zaira Salvador (embryologist).

The diagnosis of Morris syndrome is usually made in girls when they reach puberty, between the ages of 12 and 15, since the first warning sign is the absence of menarche (first menstruation).

In a first gynaecological check-up, an ultrasound will show that the girl does not have internal reproductive organs. Then, to confirm whether it is Morris syndrome, a hormonal blood test and a karyotype test will be performed.

Suggested for you

We have talked about the options that exist for women with SIA to become mothers. If you want to get more detailed information about this topic and decide upon the best option for your situation, we recommend you read the following articles:

How to adopt a child?

What's surrogacy? Everything you need to know

Surrogacy vs. Adoption- what are the differences?

We make a great effort to provide you with the highest quality information.

🙏 Please share this article if you liked it. 💜💜 You help us continue!


Batista RL, Costa EMF, Rodrigues AS, Gomes NL, Faria JA Jr, Nishi MY, Arnhold IJP, Domenice S, Mendonca BB. Androgen insensitivity syndrome: a review. Arch Endocrinol Metab. 2018 Mar-Apr;62(2):227-235.

Chen MJ, Vu BM, Axelrad M, Dietrich JE, Gargollo P, Gunn S, Macias CG, McCullough LB, Roth DR, Sutton VR, Karaviti LP. Androgen Insensitivity Syndrome: Management Considerations from Infancy to Adulthood. Pediatr Endocrinol Rev. 2015 Jun;12(4):373-87.

Döhnert U, Wünsch L, Hiort O. Gonadectomy in Complete Androgen Insensitivity Syndrome: Why and When? Sex Dev. 2017;11(4):171-174.

Souhail R, Amine S, Nadia A, Tarik K, Khalid EK, Abdellatif K, Ahmed A. Complete androgen insensitivity syndrome or testicular feminization: review of literature based on a case report. Pan Afr Med J. 2016 Nov 28;25:199.

FAQs from users: 'Can Morris syndrome be prevented?', 'Is there any treatment for Morris Syndrome?' and 'How is Androgene Insensitivity Syndrome diagnosed?'.

Read more


 Zaira Salvador
Zaira Salvador
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Romina Packan
Romina Packan
Babygest Staff
Editor and translator for the Babygest magazine in English and German. More information about Romina Packan

Find the latest news on assisted reproduction in our channels.