FSHB rs11031007: Understanding Reproductive Genetic Associations
The rs11031007 variant is a common genetic marker located near the FSHB gene, which plays a critical role in human reproduction. Research indicates this variant is associated with variations in follicle-stimulating hormone (FSH) levels, as well as traits such as dizygotic twinning and the timing of menopause.
What each genotype means
Typical gonadotropin baseline
You carry two copies of the common C allele near the FSHB gene. Research indicates that this genotype is linked to standard baseline follicle-stimulating hormone (FSH) production and average population rates of spontaneous multiple ovulation and dizygotic twinning. Because reproductive outcomes rely on multiple genetic and environmental factors, this variant alone does not predict fertility.
Carried by approximately 70% to 75% of individuals of European ancestry and is the predominant genotype across most global populations.
Modestly increased twinning likelihood
You carry one copy of the T allele in the promoter region of the FSHB gene. In genetic association studies, this allele is linked to slight increases in pituitary FSH transcription and an approximately 15% to 20% higher relative chance of spontaneous dizygotic twinning in mothers. Evidence is currently limited to broad statistical associations and does not determine personal fertility or medical outcomes.
Carried by roughly 25% to 28% of people of European ancestry, with lower observed frequencies in East Asian populations.
Higher dizygotic twinning association
You carry two copies of the less common T allele near the FSHB gene. Research indicates this genotype is associated with higher circulating follicle-stimulating hormone (FSH) concentrations and an elevated relative likelihood of spontaneous double ovulation and dizygotic twinning. These findings represent population-level tendencies rather than a certainty of conceiving twins or an indicator of reproductive disorders.
Carried by roughly 2% to 3% of individuals of European ancestry and is rare in most East Asian populations.
What is the rs11031007 Variant?
The rs11031007 variant is a single nucleotide polymorphism (SNP) situated in the regulatory region upstream of the FSHB gene. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. This specific variant is located within a highly conserved genomic region, which often suggests that the area serves an important biological function, such as controlling how genes are turned on or off. By residing in a regulatory element, rs11031007 may influence the expression levels of the nearby FSHB gene, rather than changing the structure of the protein it produces. Scientists study these regulatory variants to understand how subtle differences in our genetic code can lead to observable differences in physiological traits, such as hormone regulation and reproductive health.
The Role of the FSHB Gene
The FSHB gene provides instructions for making the beta subunit of follicle-stimulating hormone (FSH). FSH is a vital hormone produced by the pituitary gland that travels through the bloodstream to signal the gonads. In females, FSH is essential for the maturation of ovarian follicles, which contain eggs, and it plays a key role in the ovulation process and the synthesis of other reproductive hormones. Because FSH is so central to the reproductive cycle, even minor changes in its production or regulation can have downstream effects on fertility-related milestones. The FSHB gene is part of a complex feedback loop involving the brain and the reproductive organs, ensuring that hormone levels remain within a range necessary for healthy reproductive function throughout a person's life.
Research and Reproductive Associations
Large-scale genome-wide association studies (GWAS) have linked variants in the FSHB locus to several reproductive traits. Research has observed that certain alleles at this locus are associated with higher serum FSH levels, which in turn correlate with earlier ages at menarche and menopause, as well as differences in lifetime parity. Notably, this locus has been identified as a maternal susceptibility factor for spontaneous dizygotic (fraternal) twinning. While these statistical associations are robust in large cohorts, it is important to note that the evidence strength for any individual's specific outcome remains limited. Genetics is only one piece of a complex puzzle that includes environmental, lifestyle, and other biological factors. These findings are intended for educational purposes and do not provide a predictive diagnosis for any individual's reproductive health or fertility status.
Population Frequency and Interpretation
The rs11031007 variant is considered a common SNP, meaning it is found frequently across diverse human populations. Because it is common, it is a normal part of human genetic variation rather than a rare mutation. When interpreting information about this variant, it is crucial to understand that statistical associations found in research studies describe trends across large groups of people, not the experience of a single individual. A reader cannot use this information to make medical decisions or predict personal fertility outcomes. If you have questions about your reproductive health, hormone levels, or family planning, the most appropriate course of action is to consult with a qualified healthcare provider or a fertility specialist who can evaluate your specific clinical history and needs.
How common is this variant?
The rs11031007 variant is a common genetic marker observed across various global populations, with its specific allele frequencies varying by ancestry.
Frequently asked questions
Does having this variant mean I will have twins?
No. While this variant is statistically associated with an increased likelihood of dizygotic twinning in large populations, it is not a diagnostic tool. Many factors, including age, family history, and environmental influences, contribute to the probability of having twins.
Can I use this SNP to predict my fertility?
No. Genetic variants like rs11031007 provide information about biological trends in large groups, not individual predictions. Fertility is a complex trait influenced by many genes and lifestyle factors, and this SNP cannot be used to assess your personal fertility.
Should I get my FSH levels tested because of this variant?
You should only undergo medical testing if recommended by your doctor. If you have concerns about your reproductive health or hormone levels, discuss them with a healthcare professional who can order appropriate clinical tests based on your medical history.
Is this variant considered a disease-causing mutation?
No. This is a common regulatory variant, not a disease-causing mutation. It is part of the normal range of human genetic diversity and is associated with natural variations in reproductive traits.
Sources & further reading
Educational information only, last refreshed 10/20/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Promoter-adjacent variant linked to FSHB expression, influencing basal follicle-stimulating hormone levels, menstrual cycle duration, and twinning propensity.
Pathogenic loss-of-function variant causing isolated follicle-stimulating hormone deficiency leading to hypogonadotropic hypogonadism.
Functional promoter variant in FSHB influencing serum FSH concentrations and reproductive lifespan.
Variant in the promoter region of FSHB associated with circulating follicle-stimulating hormone levels, age at menarche, and reproductive lifespan.
Located in the promoter of FSHB (c.-211G>T), this variant downregulates follicle-stimulating hormone transcription and is strongly associated with male infertility traits (oligozoospermia) and altered female reproductive lifespan.
Variant in the promoter region of FSHB associated with altered follicle-stimulating hormone levels, timing of menarche, and female reproductive lifespan.