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Table of Contents
Genetics of toe length
Summary
You may have heard that the length of your big toe compared to your second toe is a simple genetic trait, that having the big toe shorter than the second toe is dominant. This is not true! People don't fall into two discrete categories, "big toe longer than second toe" vs. "big toe shorter than second toe." Plenty of people have both toes the same length, and some people (like me!) have the big toe longer on one foot, and the second toe longer on the other foot. Studies of families have shown that toe length is not a simple genetic trait. Don't worry if your family has two long-big-toe parents and a short-big-toe child, and if you're a teacher, don't use toe length as an example of a simple genetic trait.
Are there just two kinds of toe lengths?
It's not real common, but some biology teachers have used toe length as an example of a genetic trait. They divide people into two categories, those with their second toe longer than their big toe, and those with the second toe shorter than the big toe.
Most studies of toe length have just recorded whether the second toe extended farther or less than the big toe. Results varied depending on whether the toes were pressed flat or allowed to curl naturally, but generally showed that the majority of people had big toes that extended further than the second toe (Merritt Hawkes 1914, Papadopoulos and Damon 1973, Hajaghazadeh et al. 2018).
Mukherjee and Raghavendra Rao (1976) actually measured toe lengths (from the back of the heel to the tip of the toe) and calculated the difference in lengths as a percentage of the length to the big toe. Their results showed that there weren't very many people with the big toe just slightly longer than the second toe, but otherwise, the variation was pretty continuous, not two distinct categories.
I did an image search for painted toenails and arranged the images from longer big toes to longer second toes. This makes it pretty clear that there aren't just two distinct categories of toe length.
Some people (including me) have the second toe longer on one foot, with the big toe longer on the other foot. Merritt Hawkes (1914) found that 6% of people had one foot in each category, further evidence that dividing people into two categories of toe length is arbitrary.
Family studies
Merritt Hawkes (1914) compared British parents and offspring, with the following results (individuals who were L on one foot and S on the other are omitted):
| Parents | S offspring | L offspring |
|---|---|---|
| S×S | 8 | 1 |
| S×L | 10 | 58 |
| L×L | 0 | 154 |
She concluded that L was "irregularly dominant" over S. In reality, these data are consistent with S being dominant over L. If L were dominant, some of the L×L matings would be of two heterozygotes, and some of their offspring would be S.
Beckman et al. (1960) compared Swedish parents and offspring, with the following results:
| Parents | S offspring | L offspring |
|---|---|---|
| S×S | 3 | 1 |
| S×L | 6 | 31 |
| L×L | 3 | 56 |
While there is clearly a genetic component, the one L offspring of S×S parents does not fit the model of S being recessive, while the three S offspring of L×L parents do not fit the model of S being dominant.
Papadopoulos and Damon (1973) performed a similar study on four tribes in the Solomon Islands:
| Parents | S offspring | L offspring |
|---|---|---|
| S×S | 74 | 46 |
| S×L | 63 | 102 |
| L×L | 51 | 137 |
In this study, S parents are more likely to have S offspring than are L parents, so there seems to be some genetic influence on toe length. However, if S was recessive, two S parents could not have an L child, yet more than a quarter of the children of S×S matings are L. The large number of S individuals with two L parents means that L is not caused by a recessive allele.
Mukherjee and Raghavendra Rao (1976) treated relative toe length as a continuous, quantitative trait, instead of dividing people up into L and S. There was a correlation between parents and offspring, which indicates there is a genetic influence on relative toe length.
Twin studies
Kaplan (1964) found that out of 63 pairs of identical twins, none had one L twin and one S twin, while 11 out of 44 pairs of non-identical twins had one L and one S twin. This clearly shows a strong genetic influence on toe length, although it does not tell us whether toe length is controlled by one or more than one gene.
Further research
It seems pretty clear that relative toe length is affected by some mix of the environment, developmental accidents, and one or more genes; it is not controlled by a single gene with two alleles. Further genetic research seems unnecessary.
I suppose it would be worthwhile to carefully measure the relative toe lengths in a large sample of people, to confirm that it really is a continuously varying trait. It's difficult to measure toes accurately, because you need to flatten the toes out, without putting so much pressure on them that they get longer. An accurate study of toe length would also require handling the smelly feet of a large number of strangers, so it wouldn't be my first choice of research project.
References
Beckman, L., J.A. Böök, and E. Lander. 1960. An evaluation of some anthropological traits used in paternity tests. Hereditas 46: 543-569.
Hazaghazadeh, M., R.E. Minaei, T. Allahyari and H. Khalkhali. 2018. Anthropometric dimensions of foot in northwestern Iran and comparison with other populations. Health Scope 7: e14063.
Kaplan, A. R. 1964. Genetics of relative toe lengths. Acta Geneticae Medicae et Gemellologiae 13: 295-304.
Merritt Hawkes, O. A. 1914. On the relative lengths of the first and second toes of the human foot, from the point of view of occurrence, anatomy and heredity. Journal of Genetics 3: 249-274.
Mukherjee, D.P., and V. Raghavendra Rao. 1976. Quantitative genetics of relative toe lengths. Journal of the Indian Anthropological Society 11: 107-116.
Papadopoulos, C. C., and A. Damon. 1973. Some genetic traits in Solomon Island populations. III. Relative toe lengths. American Journal of Physical Anthropology 39: 185-190.
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This page was last revised October 26, 2026. ©2026 by John H. McDonald. Content is available under the Creative Commons Attribution-Noncommercial license.