Could very well be true.
In a British study examining condom use and reproductive health, the authors stated that "penis size could affect condom failure." The cross-sectional study looked at race factors on condom use. In this study, 18% of people of African descent, 7% of Caucasians and no Asians reported frequent breakage. In contrast, 21% of Asians, 8% of blacks and 2% of whites reported frequent complete slippage.
(British study, so Asian here probably means Pakistani/Indian)
Strange that blacks have more slippage as well. I think they have more extremely big and extremely small ones.