The show never really went into much about Breen reproductive processes, except for mentioning that they can reproduce at a very young age.
The Aliens RPG sourcebook on the other hand says that there are male and female Breen, granted of course, this is not a canon source of information.
Personally, I think that If there were female Breen, they would be indistinguishable from the males, at least when wearing their suits.
That's my two cents on the matter.
Originally Posted by SaintAdalberto
I think the Breen boil away at room temperature, which is why so little is known about their physiology. ;-)
The above mentioned sourcebook happens to support your thinking
Said sourcebook also states that the Breen are ammonia-based, have purple, blue-veined skin and multi-chambered, gelatin filled internals instead of featuring (most) major organs common to most humanoids.
Not particularly relevant to the topic, but it's an interesting theory on Breen physiology :p
it was stated by Wayon from DS9 that the Breen homeworld is not a frozen tundra but rather moderate climate and that they wear the "Cold Suits" for an unknown reason. Maybe the STO team can come up with something interesting.