It would be a mixed breed with characteristics of both. But a pure Siamese only comes from the mating of two Siamese cats.
Calico or tortoiseshell is a colour, not a breed, so your kittens will be half Siamese and half whatever breed the calico is. Male calico cats are very rare, so if you have tom kittens they are more likely to be Siamese looking; but to be honest it's a bit of a lottery. You could end up with calico cats that are small like Siamese; a larger cat with Siamese colouring; or lots of other combinations. Either way, I hope your kittens will be healthy and happy!
IMPOSSIBLE! Siamese is a breed, calico is a color and male calicos are sterile.
You can have offspring with point colorings and that is it.
You can have offspring with point colorings and that is it.
Yes I am fairly sure it can happen if both cats have the pointed gene. The pointed gene is just the markings on the siamese they are called points...the mask on the face the feet. The gene can be carried from generations back.
If your calico cat produced two kittens with Siamese markings, that indicates that she must have been mated by a Siamese tom cat. The kittens would therefore have been half Siamese.