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Behavior and handling 2 min read

Is My Crested Gecko Male or Female? How and When to Tell

How to tell a male crested gecko from a female: the hemipenal bulge, pre-anal pores, the size or age at which they appear, and why young geckos are hard to sex.

Written byHerpWise Editorial
Checked against 4 sources

Short answer

Males develop a clear bulge at the base of the tail, just behind the vent, where the hemipenes sit; females do not. The bulge is the reliable sign, but it takes time to appear. Pangea says it shows at about 5 to 9 months; ReptiFiles says at about 18 to 25 grams. Pre-anal pores may show earlier, but checking them with a magnifier is not always accurate. Until the bulge appears, treat a young gecko as unsexed.

The reliable sign: the hemipenal bulge

ReptiFiles calls sexing crested geckos fairly straightforward once they are old enough: males have a prominent bulge at the base of the tail, just behind the vent; females do not.1 The bulge holds the hemipenes, the male reproductive organs.

When it appears

Source When the male bulge shows
Pangea At about 5 to 9 months of age2
ReptiFiles At about 18 to 25 grams1

Until the bulge appears, you cannot be sure.1

Pre-anal pores: an earlier, less reliable clue

Males also have pre-anal pores, a row of small openings in front of the vent. Pangea says pores may show at 5 to 10 grams.2 ReptiFiles says some breeders try to sex geckos early by checking for pores with a magnifying glass or jeweler’s loupe, but that this is not always accurate.1

How to look

  • Let the gecko climb onto a clear surface, or a flat palm, and look at the base of its tail from below. A photo from below can help.
  • Never hold or pull the tail. Crested geckos cannot regrow a dropped tail.3
  • Keep sessions short, and wait until a new gecko has settled before handling.3

Why it matters

  • Housing. Never keep males with other geckos permanently.3 ReptiFiles warns that males housed together will fight and can injure or kill each other, and that a male and female together will mate and lay eggs.4
  • Unsexed juveniles. ReptiFiles describes a breeder who kept unsexed juveniles together until two matured into males and fought, leaving one dead.4

Common questions

Can a crested gecko be sexed as a baby?

Not reliably. ReptiFiles says some breeders try to check pores early with a magnifying glass or jeweler's loupe, but that it is not always accurate. Sex can only be confirmed once the hemipenal bulge develops, or clearly does not.

My "female" crested gecko developed a bulge. What happened?

Young geckos sold as female are sometimes males whose bulge had not yet appeared. ReptiFiles describes a breeder who kept unsexed juveniles together until two turned out to be males and fought. Separate them as soon as a bulge appears.

How big should a female be before breeding?

Pangea recommends at least 35 grams with a tail (3 to 5 grams less if tailless), with 40 grams better for a first season, and waiting until she is about 14 months old. Males can breed from about 9 months to a year.

Sources

Numbers in the text link to these sources. We checked each one on the date shown.

  1. 1Crested Gecko SexingReptiFiles. Checked Oct 29, 2026.
  2. 2Crested Gecko CarePangea Reptile (diet maker and breeder). Checked Oct 29, 2026.
  3. 3Caring for your Crested GeckoRSPCA. Checked Oct 29, 2026.
  4. 4Crested Gecko Enclosure Size & CohabitationReptiFiles. Checked Oct 29, 2026.

Update history

  • : First published.
  • : Re-checked every claim against its sources; corrected wording, numbers and attributions.

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