The couple had been in touch with some of the parents after returning to the United States, but during a visit last summer tabled a meet between all of the families through the clinic they donated to, Fertility Plus.
"We said, would you be open to a gathering with all of us together and they all said that would be great," Lawrence said.
The group gathered in December, had pizza delivered, and traded observations of Lawrence and Thiemann's similarity to their offspring, right down to matching odd- shaped toes.
"It was just fantastic. We all got along really well. It was amazing actually. It was just heartfelt," Lawrence said.
"There was definitely an amazing energy. It was emotional, to see the children and to see the connection."
Fertility Plus scientific director Margaret Merrilees says more sperm donors were needed thanks to a decline in the number of men donating, and an increase in the number of families seeking fertility treatment, or mothers going it alone.
By law all donors must be willing to be identified to children born as a result of their donation, and at 18 those children can find out the identity of their donor. Through the clinic, parents can choose to meet their donor before then if they wish.
Couples can also use the same donor's sperm for multiple inseminations. Lawrence and Thiemann's donations created four children in two families, and three children for three others.
Lawrence said he relied on the parents to give direction on what communicative approach they preferred, and had no expectation about what their relationship would be, if any.
The couple once considered adopting their own children but when that didn't pan out they decided they could help others who wanted their own families.
"It comes down to life. The greatest gift you can give is life. When we look around the world today, you see so much that's just based on negativity," Lawrence said.
"To be able to provide the gift of life to (couples) who really wish to have a family of their own...this is the greatest gift we could ever give."
Donors undergo a variety of health checks to ensure their suitability to donate, and must be aged between 18 and 45.
Counselling sessions are provided and men usually need to provide 10 bankings, of which can be used for a maximum of 10 children in four families.
Merrilees said it was "quite common" for donors to meet families they helped but when the clinic first opened in 1983 secrecy was the mode and donors had to be anonymous.
While the process could be considered lengthy, it was an "altruistic" thing to do, she said.
"Everyone at the clinic is incredibly grateful to them. It's a wonderful thing to do and makes the recipient family incredibly happy."
CAN YOU HELP?
Fertility Plus in Auckland urgently needs sperm and egg donors. Email fertlab@adhb.govt.nz or call 09 630 9842 to inquire about eligibility.
Visit fertilityweek.org.nz.