Spanish association ASPASI said one in four female children and one in seven male children suffer sexual abuse from adults, Think Spain reported.
The report said 80 percent of cases of sexual assault among minors occur within the family and 90 percent are committed by men.
The organization which seeks to eradicate child abuse said the majority of sexual assault cases go unreported so figures may actually be higher.
Yosemite climber falls 30 feet, suffers major injuries
Lytro unveils camera that can focus a photo after shooting it