I am aware of that the memory foam mattresses retain body heat, but can't find opinions on this topic for latex mattresses?  My husband tends to be very warm when others are not due to a nerve injury in his back.  When we were trying out latex mattresses, to me the latex mattress seemed to do this somewhat.

My reading on this board suggests that latex is less likely to retain body heat because of vertical air channels through the rubber. I would guess that body warmth is probably dependent on (1) bedding materials, (2) mattress casing materials, (3) mattress composition, and (4) mattress cushiness.

- Bedding materials: some sheets and mattress pads naturally retain more heat than others
- Mattress casing materials: well, they can differ in thickness and textile; some natural-fiber advocates can be vocal on the subject
- Mattress composition: specifically the parts which you're sleeping directly on (batting, polyurethane foam, latex, memory foam)
- Mattress cushiness: if you've sunk 3" into a soft mattress, the same materials will communicate/reflect more heat to you than a firmer mattress

Memory foam softens in response to heat, so your warmer bits sink further in. Memory foam is also a poor conductor of heat away from your body, so the warmed and softened memory foam will stay close to you throughout your nap. This is less true for latex, although we've been sleeping on a rather soft latex layer lately and I've found it a bit warm (but then I tend to feel warmer at night than my wife does, and it has been warmish lately). We're about to switch to a firmer latex mattress and I expect it to be a bit cooler. Before we bought this mattress we had an innerspring mattress, but it was enclosed in a vinyl bag due to my allergies and the vinyl reflected some warmth too.

I think that any surface that conforms closely to your body will tend to be warmer than one that doesn't.

I do seem to sleep slightly warmer on latex than I did on my old innerspring but its barely noticable. This is a Flobed w/ a PAB cover over it followed by 300tc cotton sateen sheets. I definitely don't think it sleeps hot at all, but again, mildly warmer than my old innerspring.

I don't know if latex retains body heat, but some I laid on did seem to warm my back.  They weren't covered in natural materials, like wool, cotton or cashmere, so I figured that had something to do with it. 

I agree with D3FI, that my latex mattress from FloBeds sleeps only slightly warmer than my conventional spring mattress did but barely noticeable.  I also sleep with 300 TC sateen sheets and sometimes 400 TC sateen sheets.   I have always slept with a latex pillow all of my life and I do not feel it sleeps warm but maybe it does slighly more than some other materials.