The transfer of spermatozoa onto children’s underwear during normal domestic laundering activities

In cases of sexual assaults involving children, biological evidence such as semen is often found on clothes rather than on intimate swabs. Two cases involving young girls were submitted to one of the AFSP BFF forensic science laboratories instigating further research into the background levels of semen on children’s underwear after being laundered, without sexual acts occurring. This study considered the potential for background levels of semen in the washing machine and the levels of semen transferred with varying laundry storage and washing arrangements. The results concur with previous studies that low levels of spermatozoa can transfer during washing; however, this study demonstrated that background levels of semen can be present on children’s clothing during domestic laundering activities which include male underwear when there are sexually active males within the household. Further, that semen can persist in the washing machine even after three washes. This study has produced data which will assist forensic scientists to evaluate cases of child abuse in a domestic setting.