biparous

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Producing two offspring in a single birth.

from The Century Dictionary.

• Bringing forth two at a birth.
• In botany, having two branches or axes: applied to a cyme.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Bringing forth two at a birth.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective producing two offspring from one pregnancy; twinning

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective producing two offspring at a time