The Braithwaites are African-American, so online, Karen Braithwaite typed in “African-American Barbie party supplies.” Her search yielded nothing. Georgia, seated next to her, was perplexed.

Despite the collection of more than 15,000 signatures of support, a Harlem mother said Mattel has rejected her plea for party supplies featuring Barbies of color. Company reps said it's not about ...