The announcement Monday by a nonprofit organization that two women with ovarian problems produced fertile eggs via in vitro fertilization using eggs from anonymous donors is good news for those struggling with infertility, including patients suffering from Turner's syndrome or experiencing menopause at a younger age.

But experts point out that Japan still lacks sufficient legislation on who will legally be the parents of the child born under such circumstances, which could cause trouble in the future.

Jiro Nudeshima, a researcher at Tokyo Foundation who is well-versed in bioethics, said he hopes the latest case will push authorities to map out sufficient legislation.