“We’re living longer, and this new middle age is becoming a time when people start to think about what they want to do with the rest of their lives. For many who haven’t had kids, they decide to reinvent themselves as parents.”  The path to parenthood comes in many ways. Beyond adoption and surrogacy, some choose in-vitro fertilization, either with donor eggs or eggs they have frozen in the past. None of this is cheap. Mr. Campanella, for example, paid about $120,000, which included legal and medical fees, and costs for the surrogate mother.  “People are so much healthier today,” said Dr. Philip Chenette, a reproductive endocrinologist at the Pacific Fertility Center in San Francisco. “I see 55-year-olds routinely mountain biking in Marin County, and if you keep a good diet and keep your weight down, you can do a lot of things with your body that you couldn’t do before. If your life expectancy is longer, why wouldn’t you want to fill that time with your kid?”  Some fertility clinics have extended the age of the patients they will accept. The cutoff at Pacific Reproductive is 55 for women (The combined age for a couple is 110). There is none at the New York Fertility Institute, in Manhattan. “We’ve had patient’s first baby delivered to 57,” said Dr. Majid Fateh, the founder and medical director.  Steve Klein, a family formation lawyer in San Diego, is also seeing older people coming through his doors. “As surrogacy has become more mainstream, people see it as a viable way to have a child, especially for people who are beyond the optimum reproductive ages,” he said. “They have money, they can provide a comfortable life, a private education. They can have nannies assist them, or one of them could be a stay-at-home parent, and they’re older and wiser and more mature. They can be a better parent than if they were younger.”  Sometimes no one is more surprised by the desire to have a child in later life than the soon-to-be-parent. Merle Hoffman, the founder and chief executive of Choices Women’s Medical Center, in Queens, said she had never wanted children.  “I saw myself leading troops into battle,” said Ms. Hoffman, now 70. “That didn’t allow for a maternal kind of orientation.” She was so clear on her decision that she terminated a pregnancy at age 32.  But when she was in her mid 50s, her husband of more than two decades died. The emptiness was palpable. “I had experienced many facets of love: sexual, devotional, parental from myself to my mother, the love of a cause. But I had never experienced what so many people experience as being the ultimate nonconditional love,” she said. “I wanted to experience what it was to love like that.”  At 58, Ms. Hoffman adopted a 31/2-year-old girl from Russia.  Friends greeted her with everything from shock to rage. “Some were like, ‘What are you, nuts? You’re too old!’” she recalled. “Some were supportive. Others were thinking, ‘Well, where’s my position in her life going to be now? Because this child will be the most important person.’”  While some people worry about the daily logistics of having a child later in life, others worry about the ethics of it.  Annie Worshoufsky MacAulay, 55, a nurse in Hartford, is planning to adopt a baby with her partner, Cindy. The couple has a 6-year-old son, Nate. Ms. MacAulay has four adult children from a previous marriage.  Although she feels strong and vibrant, she does have some reservations. “My mind tells me — oh, my God, am I going to be going to his graduation on a wheelchair? Will I be around? Will people think I’m his grandma? My mind and body have a constant struggle.”  Doctors and lawyers also grapple with the ethical considerations of having a late-in-life child. In 2013, the American Society of Reproductive Medicine revised its ethics committee report on oocyte or embryo donation to women of “advanced” age.  “In view of the lack of data about maternal and fetal safety,” they concluded, “providing donor oocytes or embryos for transfer to any woman over 55 years of age, even when she has no underlying medical problems, should be discouraged.”  The risk of complications increases dramatically after 55, including pre-eclampsia, diabetes and high blood pressure.  There are health risks from older fatherhood, too. Sperm from an older man, researchers say, puts children at an increased risk for autism, schizophrenia and dwarfism. While no one has yet advised men to freeze their sperm to save for a later date, “it’s not a terrible idea,” said Dr. Chenette.  Apart from the ethical considerations, there are practical issues to take into account.  “Some lawyers will say, ‘Morally, is that really in the best interest to the child to be doing this?’” said Mr. Klein, who also runs a surrogacy center. “I say, ‘Do you have estate plans? Do you have people willing to step in as guardians? Do you have a support system in place for this child?’ A responsible lawyer will insist on this with their clients.” (Mr. Campanella appointed friends to be his son’s guardian).  For all the questions, advocates for older parents say they can provide something special for their children — and themselves.  “My father was 50 years older than me,” said Dr. Fateh. “I was in my 20s when he died, but the few years I spent with him were the best in my life. He was loving, understanding — he was mature, he’d gone through life.”  In his observations, Dr. Fateh added, “older parents are really gentle with the kids and more understanding.”  “They’re in a state of life where financially they’re more comfortable,” he added. “They spend a lot of time with the kids. In your 30s, you’re working so hard you hardly see the kid. I don’t know a single old father who regrets it.”  Make the most of your money. Every Monday get articles about retirement, saving for college, investing, new online financial services and much more. Sign up for the Your Money newsletter here.  A version of this article appears in print on August 6, 2016, on page B5 of the New York edition with the headline: Single, 54, and a New Dad: Why Some Start Families Late. Order Reprints| Today's Paper|Subscribe
Many woman and men over 50 who never had children are deciding to put their longer life spans and higher incomes to use by starting families.