A possible mistake was detected by a Dutch medical institution's investigation when up to 26 women was discovered may have been fertilized by wrong sperm at their IVF laboratory.

University Medical Center in Utretcht said that the "procedural error" occurred between mid-April 2015 and mid-November 2016 during the in-vitro fertilization.

IVF or in-vitro fertilization is the process of medication for couples who have problem in having babies due to infertility of either the male or the female. In the later procedure a sperm from the male is being mixed with the egg of the female and stored in a laboratory to encourage fertilization, when fertilization and cell division is taking place these develop into an embryo. Then the embryo is transferred in the uterus of the female after two to three weeks.

According to Fox News, it was noticed that "during fertilization, sperm cells from one treatment couple may have ended up with the egg cells of 26 other couples. It gives possibility that the egg cells have been fertilized by sperm other than that of the intended father."

The possibility was not eliminated as happening although little chance is seen as stated by the center.

The couples were informed of the situation. Half of the women who had IVF treatment became pregnant or given birth. Some of the frozen embryos of the 26 couples were still available but the possibility that they too have fertilized not of the intended father, as The Guardian reported.

These mistakes were not the first, in 2012 a mother filed a complaint against a clinic in Singapore for negligence when it allegedly combined her husband's sperm with other person.

Another recorded incident was that of a Chinese woman when she gave birth with a child in 2010 with different skin tone and hair color from her husband.