The two women, who have been together almost 10 years, adopted Tia in Hackney, London, where they had been living for many years.
In New Zealand they wouldn't have been so lucky as the law here prevents unmarried heterosexual couples and same-sex couples from adopting.
In London, Chester and Otto, who had failed to conceive through IVF using a close friend's sperm, attended compulsory courses with other prospective adoptive parents and passed a stringent vetting process before being approved.
Chester, who has dual New Zealand and United Kingdom citizenship, said: "It was very intrusive, but it's like that for anybody who goes through it. We were lucky that we were in a society that didn't discriminate."
In fact one reason they'd felt confident enough to apply was that the Hackney Council had put up posters inviting gay people wanting to adopt to come forward.
In April 2010 the couple was approved and given about two weeks' notice that an 11-month-old girl who had spent her life with foster parents was to be theirs.
The day they brought her home after getting to know her for four days was overwhelming.
Said Chester: "We were overjoyed at having this little person coming to join us. We were quite jubilant that she was coming."
Otto couldn't stop smiling and said they both grinned for months.
"We think it's going brilliantly. She's definitely bonded with us," said Chester. "It's brilliant. If we could have more, it would just be perfect because we love her so much and have got so much joy out of having this little person in our lives."
They had hoped one day to try for a sibling for Tia, but they were in for a shock when they moved to New Zealand last month.
"I have the perception of New Zealand being quite forward," said Otto. "Why keep a law that is from 1955? We are in 2012. Not even straight couples who've been together for 22 years here can adopt as a couple."
Although New Zealand adoption law doesn't recognise Chester and Otto as people eligible to adopt, Tia is now recognised as their legal child.
"There's no doubt about her legal status here," said Chester. "We are both listed as her parents. She has New Zealand citizenship through me. She has a New Zealand passport and a British passport."
It would be fantastic if they could adopt again, but they know just how "very, very lucky" they are to have Tia.
"She completes us."
Law reflects 1950s
Back when New Zealand's Adoption Act was passed, Sid Holland was Prime Minister, the Queen was 29 years old and four men were hanged in Mt Eden.
National MP Nikki Kaye and Green MP Kevin Hague are drafting a bill that would update our 1955 adoption law which prevents gay and unmarried couples from adopting. The draft should be finished in the next few months.
Hague said: "The big issue with the adoption law is it's from 1955 and it fossilises in a variety of ways the attitudes and beliefs of 1955."
The existing law treated adoption as something of a "property transaction" and did not put the best interests of the child at the heart of decision-making. Even if a new law enabled gay or de facto heterosexual couples to adopt, the child's interests would still have to come first when deciding on the most suitable parents for a child.
As well as Kaye and Hague's bill two others that would enable same-sex adoption are in the ballot for a chance to be put before the House, or are being drafted.
Labour MP Jacinda Ardern has introduced a bill that would require the Law Commission to rewrite the law to allow same-sex couples to adopt.
And fellow Labour MP Louisa Wall is drafting a bill to redefine marriage, and therefore allow gay adoption.
