NBC NATIONAL NEWS — Wildlife experts say two mountain lion cubs recently born in California's Santa Monica Mountains are a product of inbreeding.

The problem may be due to isolation caused by urban development.

Officials say inbreeding occurs when a male cannot roam freely to find new mates.

Genetic tests indicate the cubs were the result of a lion that bred with it's own daughter.

Biologists have suggested building a tunnel under California's 101 Freeway that would allow mountain lions access to a greater area and larger breeding population.