A fingertip is your ruler with a Chihuahua
A young Chihuahua is male when his genital opening sits on his lower belly, roughly a fingertip or more away from his anus, and female when hers sits almost against her anus under the tail. At this size the structures are measured in millimetres, so vague impressions from across the room mean nothing. Apple-shaped heads, trembling, boldness, and coat colour separate nothing at all in this breed. Get close, get the light right, and compare the two openings directly, because that spacing is the whole answer in a puppy small enough to cup in two hands.
Handling the smallest patient safely
Warm your hands first, because a young Chihuahua chills quickly and shivers hard enough to blur everything you are trying to see. Work over a folded blanket on a table or your lap so a sudden startle cannot become a fall, and support the puppy's whole body with one hand while the other steadies the hips. Never dangle a Chihuahua puppy by the front legs or roll it fully onto its back against resistance. If the puppy cries, pants, or struggles, stop, wrap it against your chest to warm up, and try again later rather than winning the argument.
Spotting a male Chihuahua puppy
On a male Chihuahua, look along the lower belly for a very small rounded dot of raised skin, like a tiny button, positioned between the hind legs and the middle of the underside. Short-coated puppies show it readily, while long-coated puppies may hide it beneath a surprising amount of fine hair that needs parting with a fingertip. His testicles, at a young age, may be no more than a suggestion of fullness in front of his anus and can be entirely unnoticeable. What confirms him is that button's belly address: nothing female is raised in that spot.
Spotting a female Chihuahua puppy
On a female Chihuahua, the belly carries only a pinpoint navel scar, flat against the skin, and the real opening waits under her tail. Lift the tail gently and look for a minute vertical slit set immediately below her anus, so close that on this tiny breed the two can appear almost joined. A magnifying light or a helper holding a torch at an angle makes the distinction far easier than squinting. Her small size also means a full bladder can swell the belly and distort the view, so check before a feed rather than straight after one.
Why Chihuahua owners get fooled
The navel scar causes most Chihuahua mistakes, because on a two-pound puppy its position midway down the belly looks deceptively like a male part until you notice it lies completely flat. Visible nipples mislead owners too, though males carry a miniature row of them as well. Long coat versus short coat changes how hard the search feels, not what the search finds. Comparing the puppy against a littermate whose sex the breeder has already confirmed, ideally in the same lighting, resolves most lingering doubt in this breed.
Getting certainty without stressing the puppy
Ask the veterinarian to confirm your Chihuahua's sex at the first puppy check if the miniature anatomy leaves you hesitant, and arrange a visit sooner for any swelling, discharge, crying while passing urine, or a wet, inflamed patch under the tail. Those problems matter more than the labelling question and deserve prompt attention at this fragile size. Once the answer is settled, passing it to family and sitters through KinsLe Care Teams keeps this tiny puppy's care duties assigned against the correct profile details.