In the wake of a recent mix-up of sperm samples at Thomson Fertility Centre, specialists in the law said that the rights of the man whose semen was used in the in-vitro fertilisation (IVF) mix-up are unclear as this is an undeveloped area in the law. Assistant Professor Jack Lee noted that the Women's Charter clearly makes it a parent's duty to be responsible for the child, and since neither 'parent' nor 'child' is defined, 'parent' could be taken as biological parent - in this case, the man whose sperm was mistakenly used.