Sex Assignment
Sarah Ehtisham, Royal Manchester Children’s Hospital. Manchester, UK
Sometimes when a baby is born, it can be difficult to tell straightaway whether the baby is a boy or a girl,
and some tests need to be done before a decision can be made.
This is understandably a difficult time for the family and also for the health professionals involved, as
usually the first question asked is “is it a boy or a girl?". This is a situation that is well-recognised, although
rare, and as parents you are not alone in what you are experiencing at this difficult time as this can affect
approximately 1 in 4500 infants born.
Sex assignment refers to the process of determining whether the baby is male or female, as it is important
that this is an informed decision and not a ‘best guess’.
There are a number of issues to take into consideration at this delicate stage:
What the baby looks like?
As babies develop within the uterus, boys and girls initially look identical and physical changes which
distinguish the sexes start to appear at 7 weeks of pregnancy. These changes may be partial, making it hard
to tell if this is a boy or a girl. The medical team will undertake a detailed examination of your baby, looking
in detail at the appearance of the genitals. They will also do a general check-up to ascertain if the difficulty
determining your baby’s sex is part of a wider condition with other features.
What the baby’s genetic sex is?
One of the initial tests will be a chromosomal test called a Karyotype, which is a blood test to determine
what sex chromosomes your baby has.
Chromosomes are packets of genetic code which determine the blueprint for our body. Most people’s cells
contain 46 chromosomes, which are arranged into 23 pairs. You can think of these chromosomes as the
blueprint or plan from which the developing baby grows. We inherit one of each pair from each parent and
this is how children get features from both parents. The 23rd pair of chromosomes are the sex
chromosomes which carry some of the coding for a number of features that vary between the sexes. There
is also some information which can affect the baby’s sex on the other chromosomes 1-22.
dsdfamilies.org – info received July 2011; info to be reviewed by 31 May 2012
There are two types of sex chromosomes; either an ‘X’ shape or a ‘Y’ shape. In general, girls inherit one X
chromosome from each parent, giving them 2 ‘X’ chromosomes (which is written as Karyotype 46, XX). In
contrast, generally boys inherit an ‘X’ chromosome from their mother and a ‘Y’ chromosome from their
father, giving them an ‘X’ and a ‘Y’ chromosome (which is written as Karyotype 46, XY). In rare situations
other combinations are possible.
The Karyotype blood test is just a count of the chromosomes to see if the baby is XX or XY. The result does
not tell us the sex of the baby, just what the blueprint was. It is possible to have a girl with XY
chromosomes and a boy with XX chromosomes. In these cases further tests are needed to understand why
the physical appearance is different from the blueprint.
What hormones are being made?
Hormones are chemical signals in the body which can affect the development of the internal organs and
the appearance of the genitals. The medical team may undertake some blood and urine tests to determine
which hormones are being made and how the body responds to the hormonal signals. Both boys and girls
make ‘male-hormones’ known as androgens.
It is possible for a baby with XX chromosomes to be exposed to too much androgen and appear malelooking or virilised. It is also possible for a baby with XY chromosomes to appear completely female because
no androgens are being made or because the body is unable to respond to androgens. It is also possible for
babies with XX or XY chromosomes to have an in-between appearance depending on how much androgens
they are exposed to and responding to, hence the chromosome test does not always determine the most
appropriate sex to raise the child in.
What sex-organs are present?
Whilst the baby is developing, the sex-organs or gonads start as a common pair of structures which change
and develop during the early stages of the pregnancy into either ovaries (female sex organs) or testes (male
dsdfamilies.org – info received July 2011; info to be reviewed by 31 May 2012
sex organs). It is important for the team looking after your baby to determine what sex-organs your baby
has and also what other internal structures such as a uterus are present. There may also need to be some
tests to determine how well the ovaries/testes function.
Sex assignment
The results of the tests may take some time to come back, making this phase seem like a long wait. The
results will form the basis of the discussion about how best to raise your baby and the decision about what
sex to raise the baby in will be made jointly with the family and the health professionals. Important factors
that will guide the discussion will be what the diagnosis is and what we know about other people with the
same diagnosis, what the implications are for sexual function in future life, and for future fertility. Once a
decision has been made, the baby can be named and the birth can be registered.
How to cope?
Families have different reactions to this complex waiting time, from feeling completely overwhelmed by
the situation and wanting to hide away until a decision is made, to being open with relatives and close
friends that the baby’s sex is unclear and further tests are underway. You may wish to delay announcing
the birth until the initial assessments are complete; or you may wish to involve some close relatives at this
stage, who may be able to help and support you. It may be helpful to have a member of the medical team
examine your baby in front of you to show you what issues there are, and explain the appearance. This can
help to understand the particular issues for your baby, as often the physical appearance is more subtle than
the images brought to mind once you are told your baby’s sex is unclear. It is of value to write down your
questions and any fears you have, and discuss them with the team so that they can be addressed.
It may be best to try not to think of your baby as a boy or a girl until a decision has been made. You may
wish to give your baby a neutral name or nickname during this time, as that may help you relate to your
infant. It is important that your baby’s emotional needs are met and that you have time to get to know
them and bond with them. The hospital will be keen that you stay close to your baby and try and do all the
feeding and changing and holding that helps you bond with your baby. The team will have experienced
professionals who can help at this time and may wish to keep the baby in hospital until the matter is
resolved. They can help and advise about what and how to tell relatives. There may be a social worker or
psychologist with the team who can help you cope and provide additional support at this difficult time. In
some circumstances it is of value to delay the registration of the birth to provide valuable time to complete
the tests and come to a decision without pressure.
dsdfamilies.org – info received July 2011; info to be reviewed by 31 May 2012
Sex reassignment
As a result of this careful sex assignment process, the majority of infants have an excellent long term
outcomes and are comfortable with the sex they are raised in. In some rare situations, as the child grows
and develops, they may decide they do not feel comfortable with their assigned sex and they may wish to
think about changing their sex assignment. Whilst this is a very unusual occurrence, awareness of this has
led to reluctance in certain situations to undertake any irreversible surgery until the individual is old
enough to participate in the decision.
This information has been producedto help understand the complex process of sex assignment. Each
situation is individual and will be discussed in detail with the family and the health professionals involved.
dsdfamilies.org – info received July 2011; info to be reviewed by 31 May 2012