"Everybody is telling me it's unethical what I am doing," said Evans. "But I raised him and he wanted children. I can't get him to film school at UCLA and I couldn't help him live his dream because someone has taken it away from him."
For Evans, the idea came as the family was preparing for her son's inevitable death. She discussed the idea with her longtime boyfriend, her ex-husband, her older son and other family members, who offered to be part of the child's life.
"He was an old soul and wanted kids," Evans said of Nikolas, who was interested in filmmaking, politics, music and old movies. She said he specifically said he wanted three children, all boys.
If the child is a boy, she said she would name it after her son's favorite author, Hunter S. Thompson.
"Nikolas had talked to me about how I was an only child and his cousin was an only child," said Evans. "He was going to fill my Christmases and birthdays with grandchildren."
(Just this week, Nikolas' assailant, Erik Skeeter, was sentenced to 10 months probation for manslaughter in a plea bargain.)
Evans sought permission from a probate judge to take ownership of the sperm and Nikolas' body was chilled to no more than 39.2 degrees.
A urologist donated her services and after five of his organs were donated, she retrieved Nikolas' sperm.
Finding an egg donor who will undergo injections and tests will cost at least $20,000. Hiring a surrogate to be inseminated and to carry the child could cost another $50,000.
But there are many challenges ahead. There is no guarantee Nikolas' sperm is viable or that in vitro fertilization will be successful.
Sperm must be collected within 24 to 36 hours of a death -- a "gray window" -- and even then, it may not be viable, according to Albert Anouna, director of the Sperm and Embryo Bank of New Jersey. Nikolas' sperm was collected 31 hours after death.
The cost for surgical removal is about $3,000, according to Anouna, whose company has been asked to do five or 10 this year -- "not exactly an everyday occurrence."
Only about 1 in 500 requests are utilized, he said.
"I am not a psychologist, but the reason is that it's part of a closure," said Anouna told ABCNews.com. "The individual who asks for it either changes his mind or it's too expensive."
"It's the happiest when you get a thank you note," said Anouna, who has seen two successful pregnancies since he founded his company in 1981.
But often, post-mortem sperm retrieval itself is a failure.
In one case, Gisela Marrero of New York City had her longtime boyfriend's sperm retrieved post-mortem. Johnny Quintana, a concierge and auto mechanic, collapsed while watching television at age 31.
"The day before he passed away, we talked about planning for our future, buying an apartment and having another child," Marrero told the Daily News. "This was his wish. It's the last thing I can do for him."
Because Anouna's sperm bank follows strict ethical codes, Quintana's family had to go to court to prove the sperm was intended for one specific recipient who had an intimate relationship with the deceased.
Quintana's body was kept in cold storage at Jacobi Medical Center with an ice bag on his testicles. Semen was collected, but there was not enough sperm for artificial insemination.