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Telling the difference between a male and female leopard gecko takes a bit of practice, but the physical markers are consistent once you know where to look. I sex Geek and any other leo I work with the same way every time: underside inspection, checking three specific features in sequence. This guide covers each one and explains what you are actually looking for.
Why Knowing the Sex Matters
Male and female leopard geckos look nearly identical to the untrained eye, but the sex affects the care you provide in a few important ways.
Housing is the most immediate concern. Males are territorial and will fight if kept together, sometimes seriously. Knowing which animals are male is essential before putting multiple geckos in the same enclosure. Females can generally cohabit in a large enough space, but males cannot. For a full breakdown of what works and what does not, see our guide on whether leopard geckos can live together.
Health risks also differ by sex. Females can lay infertile eggs even when kept alone, and are at risk of ovulation complications and egg binding. Males can experience hemipenis prolapse. Knowing the sex helps you recognise the relevant warning signs and plan for them.
How To Tell If a Leopard Gecko Is Male or Female
Leopard geckos are sexually dimorphic (there are physical differences between the sexes) but most of those differences are on the underside near the vent and tail base rather than visible from above. Here are the four things to check.
1. Hemipenal Bulges
This is the most reliable indicator. Hemipenal bulges are found only in males. Females do not have them. The hemipenes are the male reproductive organs, and they sit beneath the skin on either side of the tail base, creating two visible bulges just behind the vent.
To check for them, look at the underside of the gecko near the base of the tail. On a male, you will see a clear bulge on both sides. On a female, the area is smooth and flat. In my experience this is the quickest check. If the bulges are visible, you have a male.
Important: Some sources suggest pressing the area to cause the hemipenes to protrude. Do not do this. It carries a real risk of hemipenis prolapse and causes unnecessary stress. If the bulges are visible, that is all the confirmation you need. If you cannot see them clearly, move on to the other markers.
2. Femoral Pores
Femoral pores run in a line along the underside of the hind legs, on the upper thigh. Both males and females have them, but in males they are large, dark, and clearly visible. They look like a row of prominent dots, sometimes resembling blackheads if clogged. In females they are faint and difficult to see without magnification.
Males use these pores to release pheromones during mating season, which is why they are so much more developed. Seeing prominent femoral pores is a strong secondary confirmation that you have a male.
3. Preanal Pores
Preanal pores sit just in front of the vent, arranged in a V-shaped row. They serve a similar function to femoral pores (releasing pheromones and sometimes a waxy substance) and follow the same pattern: large and visible in males, faint in females.
When you are checking femoral pores, check the preanal pores at the same time. You are already looking at the same area of the gecko. If you see both the femoral row and the V-shaped preanal row clearly, combined with hemipenal bulges, you have a male with a high degree of confidence.
4. Size and Build
Size alone is not a reliable indicator when you only have one gecko, but it is useful when comparing multiple animals side by side. Males are generally larger and more heavily built, with a broader head and neck. Females typically reach 7 to 9 inches and 50 to 75 grams at maturity. Males reach 9 to 11 inches and 70 to 90 grams.
There is some overlap at the extremes. The smallest males and largest females can be similar in size, which is why size works best as a supporting indicator rather than the primary one. Use it to reinforce a conclusion you have already drawn from the anatomical markers. For more on how size develops over time, see our guide on how big leopard geckos get.
Male vs Female: Summary of Differences
| Feature | Male | Female |
|---|---|---|
| Hemipenal bulges | Present: two clear bulges behind vent | Absent: smooth behind vent |
| Femoral pores | Large, dark, clearly visible | Present but faint, hard to see |
| Preanal pores | Prominent V-shaped row above vent | Present but faint |
| Adult size | 9–11 inches, 70–90g | 7–9 inches, 50–75g |
| Head and neck | Broader and more muscular | Narrower |
| Temperament with others | Territorial toward other males | Generally more tolerant |
| Unique health risks | Hemipenis prolapse | Egg binding, infertile egg laying |
Can You Sex a Baby Leopard Gecko?
Not reliably from physical markers alone. Hatchlings are only 3 to 4 inches long and the anatomical differences have not developed. The hemipenal bulges, femoral pores, and preanal pores are all too underdeveloped in young animals to give a clear reading.
The earliest most experienced keepers attempt to sex a leopard gecko is around four months, but six months is a more reliable minimum. Some males will not show clearly developed anatomy until closer to a year old. If you have bought from a breeder, ask them about the incubation temperature. Higher temperatures (around 90°F) produce predominantly males, while lower temperatures (around 80°F) produce predominantly females, with 87°F giving roughly an even split. This is not a guarantee, but it gives you a starting point before the gecko is old enough to confirm visually.
Tip: Wait until at least six months before attempting to sex your gecko. Doing it earlier is unreliable and causes unnecessary handling stress. Most males will be clearly identifiable by six months; some may take longer.
How To Handle a Leopard Gecko for Sexing
The main challenge with sexing leopard geckos is keeping them calm enough to get a clear look at the underside. A gecko that is stressed or wriggling will be difficult to examine and at risk of dropping its tail. Getting the handling right matters as much as knowing what to look for.
Do not attempt this with a gecko that is not already comfortable being handled. If you have recently brought the gecko home, wait several weeks until it has settled in and is relaxed during routine handling sessions before trying to sex it.
When you are ready, approach calmly and let the gecko walk onto your hand rather than grabbing it. Once it is settled in your hand, gently slide your fingers apart so you can look at the underside without flipping the gecko over. Looking up from below is far less stressful for the gecko than turning it on its back. If the gecko becomes agitated or tries to pull away, put it down and try again another time. Do not force the process.
What age can you tell a leopard geckos gender?
The earliest reliable age is around six months. Some keepers attempt it at four months with experience, but the physical markers are not fully developed until later. Males are usually clearly identifiable by six months, though some individuals develop more slowly and may need another few months before the anatomy is obvious.
What age is a leopard gecko fully grown?
Leopard geckos typically reach sexual maturity at around one year and stop growing by 18 months. If you want to be completely certain of the sex based on size comparison, waiting until 18 months gives you the most reliable reading. The anatomical markers (bulges and pores) are usually readable well before that.
Can two male leopard geckos live together?
No. Male leopard geckos are territorial and will fight when housed together. This can result in serious injuries including lost toes, tail damage, and bite wounds. Two males should never share an enclosure regardless of its size.
Do female leopard geckos lay eggs without a male?
Yes. Female leopard geckos can lay infertile eggs even when kept alone and with no exposure to a male. This is sometimes called a clutch of slugs. It is a normal biological process but can be physically taxing on the female, so calcium supplementation and monitoring are important for females kept alone.
Is a leopard gecko with no visible bulges definitely female?
Not necessarily, especially in young or juvenile animals where the anatomy may not yet be developed. If a gecko is under six months old and shows no visible bulges, it is too early to make a confident determination. In an adult gecko with no visible bulges, no prominent pores, and a smaller build, female is the likely conclusion, but checking all three markers together gives the most reliable result.
