How to Sex a Crested Gecko: Pore ID for Breeders
Most breeders mis-sex crested geckos before 6 months. Learn the pore identification technique that separates confident breeders from guessers, with age, angle, and lighting tips.
A seller at a 2024 reptile expo handed a buyer a juvenile labeled "female proven het axanthic" for $420. Eight months later, the gecko developed a hemipenal bulge and a crisp row of pre-cloacal pores. That "female" was a male, and because the buyer had already built a breeding project around it, every pairing plan had to be scrapped.
Mis-sexing crested geckos is one of the most consequential beginner mistakes in the hobby, and it almost always comes from checking the wrong feature at the wrong age.
So what should you actually be looking at, and when?
Published 2026-06-03.
TL;DR
- Crested geckos cannot be sexed reliably before 10-15 grams body weight, cloacal anatomy is too undeveloped before that.
- Males develop a hemipenal bulge posterior to the vent and a clear row of pre-cloacal pores; females lack both.
- Pore visibility depends on angle, lighting, and how well the animal is cooperating, eversion technique is not required.
- Possible-het males and females inherit axanthic and other recessives at identical rates, sex does not change genetic probability.
- When in doubt, weigh the animal and check again in 4-6 weeks rather than guessing.
Frequently asked questions
At what age can you sex a crested gecko?
Weight is more reliable than age. Most experienced breeders wait until 10-15 grams before making a confident sex call. Hatchlings are typically 2-3 grams and unsexable. A gecko can reach 10 grams anywhere from 2 to 5 months old depending on feeding and temperature, so track grams, not weeks.
What do male crested gecko pores look like?
In mature males, pre-cloacal pores appear as a V-shaped or arc-shaped row of small, slightly raised, waxy or yellowish dots just anterior to the vent. They become more obvious with age. In females, pores are either absent or present only as faint, flat dots with no waxy secretion and no clear row formation.
Can you sex a crested gecko by size?
No. Size alone is not a reliable sexing method. Adult male crested geckos tend to be smaller and slimmer than females, which is counterintuitive. Individual variation is too large in juveniles for size to be diagnostic. Always use ventral anatomy: the hemipenal bulge and pre-cloacal pores.
What is the hemipenal bulge in crested geckos?
The hemipenal bulge is the visible widening at the tail base just behind the vent in male crested geckos. Males have paired hemipenes stored there, creating a rounded widening before the tail tapers. Females have a flat, uniformly tapering tail base with no widening posterior to the vent.
Do male and female crested geckos carry morphs differently?
No. All proven crested gecko morphs (Lilly White, Axanthic, Cappuccino, Soft Scale, White Wall) are autosomal, meaning they are located on non-sex chromosomes. Males and females inherit and express every morph at identical rates. Sex has no effect on morph probability.
Is it safe to manually evert the hemipenes to sex a crested gecko?
Manual eversion is not necessary for routine sexing and carries injury risk if done incorrectly. External anatomy (hemipenal bulge and pore row) is sufficient at the right age and weight with good lighting. Leave eversion to experienced reptile veterinarians if there is a clinical reason for it.
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