How Does 46,XX Testicular DSD Affect Final Adult Height?

Yes, having 46,XX testicular DSD (sometimes referred to in older medical literature as XX male syndrome) can influence final adult height. Because individuals with this condition usually lack a full Y chromosome, their final adult height is typically shorter than the average typical 46,XY male, but often taller than the average typical 46,XX female.

While these population averages provide a helpful baseline to answer questions about expectations, human stature is highly complex. There is no validated mathematical formula or single height prediction based purely on your diagnosis. Your final adult height will be unique to you and influenced by your family genetics, bone age, and pubertal hormone levels ^[1].

The Role of Genetics and the Y Chromosome

The Y chromosome contains specific genetic sequences that contribute to overall adult height ^{[2] [3]}. In 46,XX testicular DSD, the absence of these Y-specific growth sequences is one reason why medical literature notes that affected men are often shorter relative to the general 46,XY male population ^{[1] [4]}.

When discussing genetics, it is helpful to understand a few key factors:

• The SRY Gene: In the most common form of 46,XX testicular DSD, the SRY gene (the gene responsible for initiating typical male testicular development) is present and has usually been transferred to one of the X chromosomes ^[2]. However, some individuals are SRY-negative, meaning their condition is caused by entirely different genetic pathways ^[5]. While the SRY gene initiates physical development, it does not independently determine how tall you will grow.
• The SHOX Gene: The SHOX gene is essential for healthy bone growth. Because this gene is located in a pseudoautosomal region shared by both X and Y chromosomes, a typical 46,XX person has two functional copies of this gene, just like a typical 46,XY person. However, if a structural rearrangement of the chromosomes disrupts or deletes the SHOX gene, it can lead to unexpectedly short stature ^[6].
• Family Genetics: Just like anyone else, one of the most reliable predictors of your potential height is the height of your biological parents.

Hormones, Puberty, and Growth Plates

Hormones play a critical role during the teenage growth spurt. Both testosterone and estrogen—much of which is naturally created by the body converting testosterone into estrogen—are vital for growth and for eventually signaling the growth plates in your bones to close. Once growth plates fuse, a person’s height is final.

Many individuals with 46,XX testicular DSD develop hypergonadotropic hypogonadism during or after puberty ^{[7] [8]}. This is a clinical condition where the testes do not produce enough testosterone on their own, causing the pituitary gland in the brain to produce higher levels of signaling hormones (LH and FSH) to compensate ^[8].

If your body is not producing sufficient testosterone, an endocrinologist may recommend testosterone replacement therapy (TRT) ^{[7] [9]}. If TRT is discussed, it is important to know:

• TRT is prescribed primarily to support healthy pubertal development, sexual function, bone health, and overall well-being—not as a guaranteed way to increase final height ^[9].
• The timing and dose of TRT must be carefully managed with a specialist. Early or excessive testosterone exposure can prematurely advance bone maturation (closing the growth plates early), while delayed treatment can alter the typical timing of puberty ^[7].
• TRT will not lengthen bones after the growth plates have already fused.

Uncertainty about physical development can be incredibly stressful for teens and their parents. Your multidisciplinary care team will monitor your growth velocity and bone age to ensure that any hormone therapy supports your healthiest possible outcome.