Kim and Kanye's Surrogate is a Fit, Married Mom in Her 20s

Kim Kardashian and Kanye West sure know how to pick 'em -- surrogates that is -- because the woman they found to carry their third child sounds like the perfect choice.

Sources familiar with the pregnancy tell us ... the couple's surrogate is an African-American woman in her 20s -- same with her husband. We're told she and her hubby have been married for 5 years, and their marriage is solid.

She's also had experience in the labor department. She's the mother of 2 small boys, so she knows the drill.

The surrogate's a college grad, so maybe the kid will pick up some of that through osmosis.

She's also in great physical shape, which helps with a smooth pregnancy. As we reported, she's halfway along and the baby girl is due in late January.

One more thing ... she's a registered Democrat, so it looks like the names Ivanka and Melania aren't in the cards.