People donating eggs or sperm to infertile couples no longer have the right to anonymity. Despite fears of excessive claims on donors, many children could benefit.
Eighteen-year-old Zannah Merricks from north London is among the 2,000 children conceived each year using donor sperm or eggs.
Zannah Merricks says she wants to know her genetic background
"I'm not looking for a father," she says. "I already have one."
But she does want to know a little about the man who helped create her.
"I want to meet the donor because I want to know the other half of where I'm from," she says.
Zannah will not benefit from the change in the law, as it will not be until 2023 that the first children born since its introduction turn 18 and are finally allowed to trace their biological parents.
But her case does show why it could be important to many children.
"I want to know my genetic history," she says. "And it would be interesting to know what traits I have that we might share, what we might have in common.
"There are features I have which don't relate to other members of my family.
"I'm very arty. What if he is arty too? And I'm blonde and blue-eyed.
"This sort of information is what other people just take for granted."
Susannah, who is in the middle of a gap year, has registered with UK Donor Link, which checks DNA to see if people on the database are related to each other, either as parent and child or as siblings.
"I do acknowledge that I might never find him, and that if I do, I can't expect him to be any certain way.
"It's much more likely that I'll be able to find siblings."
Zannah said she had always known how she was conceived. "I knew there was something special about me. I learned to like it more the more I knew."
Her mother Olivia, who runs the Donor Conception Network, said: "Susannah's decision to try to trace the donor is not a problem for us.
"It's just knowledge which will increase her awareness about herself.
"I think people should only be donors if they understand that need to know more about yourself."