Two women in the US have sued a sperm bank after one of them became pregnant with sperm donated by a black man instead of the white donor they had chosen.

Jennifer Cramblett was five months pregnant with donor sperm in 2012, when she and her partner learned that the Midwest Sperm Bank near Chicago had selected the wrong donor.

It came down to a clerical error: Donor No 330, a black donor, was mixed up with No 380, a white donor.

The mistake happened because the sperm bank keeps handwritten records instead of electronic ones, according to the lawsuit.

"They took a personal choice, a personal decision and took it on themselves to make that choice for us out of pure negligence," Ms Cramblett told the AP news agency.

Ms Cramblett said she decided to sue to prevent the sperm bank from making the same mistake again.

She is seeking a minimum of US$50,000 (€39,578) in damages.

The mistake was discovered when Ms Cramblett (36) and partner Amanda Zinkon (29) asked the sperm bank to reserve sperm from the same donor in the hope that Ms Zinkon would someday also have a child.

The couple said they love their mixed race daughter, Payton (2), very much and would not change anything about her. But they are concerned about raising her in the predominantly white community where they live.

Therapists have recommended that the family move to a more a racially diverse community with good schools, the lawsuit said.