You can parse a pregnancy into trimesters, divide labor into stages. You can figure that after nine months of gestation, give or take a few days, you will hold a squirming infant in your arms.
But adoption, Rachel says, meant a journey with no timetable.
Neither she nor Rob felt attached to the idea of a biological child; in fact, Rachel and a friend had always half-joked that if they reached age 35 and didn't have kids, they'd just adopt.
"But I did have a vision of how the process [of parenthood] was going to unfold. With adoption, you're kicked off that track."
Their circuitous path began with Google-searching - a low-risk first step that came easily to Rachel, a lawyer with Regional Housing Legal Services, and Rob, a software engineer.
They liked Open Arms Adoption Network because the agency offered an array of classes for prospective parents. Still, they worried: Would a birth mother choose them? What if she did, then changed her mind?
"Some of the nerve-racking part was the possibility of a ruptured adoption," Rob said. "Even if the chance is small, the pain would be large."
And Rachel bristled at some of the necessary hurdles: Provide a list of every person you've lived with since 1975. Furnish tax returns. Gather letters of reference from friends. Pass criminal background clearances. Write an autobiography.
Because Rachel is white, and the pair were open to adopting a child of color, she had to compose a separate essay. "There was a list of questions: How do you feel about becoming part of an interracial family? What will you do to learn about your child's culture?"
"If they'd asked me," Rob, who is black, jokes, "I would have said, 'lived experience.' "
There were visits from social workers, each preceded by a thorough house-scrubbing. "Adoptive parents would tell stories about how they pulled out the fridge and cleaned under it," Rachel said. "Somebody at work suggested that I bake some bread. I said, 'I'm not trying to sell the house.' "
And there was the profile book, a handcrafted album of text and photos - their life, splayed open - that would be shown to birth parents. "It's a pretty vulnerable position, really," Rachel says. "You're trying to sell yourself."
When they submitted their first draft to the social worker, she had one suggestion: "Maybe you could jazz this up a little bit."
They took her literally. Since music is a huge part of the couple's life - their first date was to a Quintron concert in Pittsburgh, and they own thousands of CDs - they added pertinent song lyrics to the book. For a section on relatives, they used Sister Sledge's "We Are Family." In another part, they included words from Whodini's "Friends."
"The one thing we kept hearing in the classes was that people were worried about certain things in their profiles," Rachel says. "But those are the things that make you who you are."
Rachel and Rob had coached themselves not to expect a match too soon; when their profile book "went live" in May 2014, a social worker said it might take until February to get a "yes." The couple sought distraction in work, though they did buy a few big-ticket baby items - the crib, the car seat - so they wouldn't be caught unprepared.
"People were saying all the time, 'Did you hear?' That can make you completely batty," Rachel says. "So we told people, 'We'll let you know. Don't ask us.' "
The call came one July afternoon when Rachel had just returned from a business trip. "I was braced for 'no,' so when the social worker said, 'You've been selected,' I was, like, 'What?' " There was more: the baby, Eva, was already born, and Rachel and Rob could pick her up the following day.
They frantically phoned and texted bosses and colleagues and made a breathless run for diapers and wipes the next morning. "I remember being at Target and feeling nauseous - so much adrenaline," Rachel says.
She still has the paper on which she scrawled notes from that life-shifting phone call: "Eva. Born June 24, 6 pounds, 11 ounces. Perfect." And she will not forget her first glimpse of her daughter, a quiet infant in a purple flowered onesie.
Rob held her first. "I had very little experience with babies before. Just holding her was a new, confusing thing: How do I hold this baby who's squirming in my arms?" He only grew more perplexed when Eva began to wail in the car. "I had no idea how to calm a child down."
Days passed in a blur of diapers and bottles. "There was a lot of: OK, how do we get through this?" Rachel says. "It was pretty whirlwindy."
But slowly, they learned their daughter's rhythms: How Eva likes her diaper to be changed right away. How she gleefully smacks down towers of blocks and shoves the monkey attachment on her ExerSaucer from one side to the other.
Over months, the mapless territory has begun to take shape. Their journey is slower now: no more popping out to a neighborhood bar, no more uninterrupted hours to read Orfeo, a book that Rachel has had since July.
Instead, there are daily Facetime chats with Rachel's mother. There is the sunrise of Eva's morning grin. And there is music: singing "Don't Cry for Me, Baby Eva" to the tune of "Don't Cry for Me, Argentina" during diaper changes; the Klezmatics tune with the "di di di" refrain that always cracks her up.
Through their open adoption with Eva's birth mother, they've already exchanged several sets of letters and pictures. They've also found common ground.
"From what we understand, music is a big part of Eva's mom's life. When she saw we had a love of music, that helped us stick out for her," Rachel says. It was that open book - a document of personality and possibility - that struck just the right note.
If you've become a parent - for the first, second or fifth time - within the last six months, e-mail us why we should feature your story: email@example.com.
Giving birth, adopting, or becoming a stepparent or guardian all count.