The author and Lincoln, then 5 months old, share a laugh on a lunch date. (Irene Haggarty)

The mothers in my “Baby & Me Yoga Fit,” class looked down from their tree poses, surprised as I poured some instant formula into a bottle.

Feeding our babies whenever they were in need was one of the most nurturing parts of the class. But with my evil formula, I was disrupting the fellow yogis in a way I never could have predicted.

“You know,” one mother said as I fed my little Lincoln, then 3 months old, “breast-feeding is optimal.”

I encountered this “breast is best” reaction at cafes, parks, even in some friends’ houses. One male friend even noticed that my husband was giving Lincoln a bottle in a Facebook posting and commented, “So you’re not breast feeding? It’s better you know?”

What I didn’t know was how to react. Did I want to be judged? Or did I feel like oversharing?

[I had to conceive my child through IVF. Now I’m racing to get an IUD.]

The truth is, I’m a breast cancer survivor, and after a double mastectomy with reconstruction, which probably saved my life, I simply wasn’t able to breast-feed.

A terrifying surprise

My husband and I rushed home on a 16-hour flight. We were in a mood that I can only describe as terrified.

My family had a history of breast cancer. My grandmother Emily Wax, whose very name I inherited, died in her early 30s.

Back then, she suffered a painful deterioration, with the cancer causing her to go blind before she passed away. Today, targeted chemotherapy and more precise surgery means that more breast cancer patients are surviving than ever.

My husband and I always wanted kids. But after six months of chemotherapy and radiation and three rounds of surgery, we had to wait five years while I was on tamoxifen, a cancer-fighting drug that can cause birth defects. Adoption agencies also required us to wait that long, since survival rates go up after five years of being disease-free.

Breastfeeding rates in 2011

[I survived breast cancer, but I hate Breast Cancer Awareness month]

“You need to cross the five-year mark. That shows us you are okay,” one agency told me.

It was a long five years of trying to be okay.

I was in my mid-30s by then, and one friend after another was getting pregnant. Every week, it seemed I opened yet another invitation to a baby shower: always the bridesmaid, never the bride. Those were moments filled with longing and jealousy that I am now ashamed of.

When the five years ended, the news was good. We were cleared to try getting pregnant. But because chemotherapy ravages fertility and I was now 37, we found ourselves saving money and signing up for in vitro fertilization.

It took two rounds of IVF to get pregnant.

This time, I could describe our mood only as happiness.

A happy time

On Jan. 29, 2014, I gave birth to a 71 / 2-pound baby boy who had a head full of light brown hair and whose ravenous appetite and old-man snore we instantly found mesmerizing, maybe in a way only parents could.

“You never gave up,” my husband said, laughing as he watched Lincoln gulp down his first two-ounce serving of formula, which my husband fed to him.

As the two of them cuddled afterward, I was in a mood that I can describe only as postpartum elation.

That is, until those I jokingly call the “breast-feeding nazis” came marching in to my room.

“You really should breast-feed,” the hospital’s lactation consultants, a.k.a. “lactivists,” said.

When I simply said, “I’m going to do formula,” they didn’t want to leave it at that.

So holding my day-old newborn on what was one of the most blissful days of my life, I had to tell the aggressive band of well-intentioned strangers my whole cancer saga.

It felt particularly exhausting because this was the first time in nearly a decade that I could forget about cancer and enjoy having had a fairly easy pregnancy and giving birth to a healthy child.

“I can’t. I had breast cancer,” I said, looking down at Lincoln and stating proudly: “But I’m just so happy to be alive and be a mother after cancer.”

Silence.

“Just try,” they advised. “Let’s hope you get some milk.”

“It may come out anyway, or through your armpits,” another advised later when I was doing the usual post-labor, slow-recovery walk through the hospital halls.

After that, when I saw those lactivists coming, I picked up my pace.

Their idea seemed so wild that I actually asked Shawna C. Willey, my breast surgeon at MedStar Georgetown University Hospital, who said, “The goal of risk-reducing surgery is to remove as much breast tissue as possible,” adding, “There should be no milk production.”

Truth was, I really didn’t want to see milk coming from anywhere other than the store. If it did, then that would mean Willey had not gotten it all and there was still tissue there for cancer to take root.

Willey added, “I think that women who have made the difficult decision to have bilateral mastectomies have already grieved the loss of not being able to breast feed. No group should make a woman feel guilty about the decisions she made . . . or make her feel inadequate about not being able to lactate.”

Around that time, a long-term study came out that compared pairs of siblings — one breast-fed, the other formula-fed. It debunked the “breast is better” mantra that I kept hearing: “Breast-feeding might be no more beneficial than bottle-feeding for 10 of 11 long-term health and well-being outcomes in children age 4 to 14,” the study found; those outcomes included body mass index, obesity, hyperactivity, reading comprehension, math ability and memory-based intelligence.

The one area in which there was a difference was asthma, which the study found was associated more with breast-feeding than with bottle-feeding.

There are, of course, dozens of studies that say breast-feeding is better for boosting nutrition and immunity in newborns. But this study was considered groundbreaking because it compared siblings rather than unrelated children, where demographic differences and whether a pregnant woman smokes or drinks can bias studies in favor of breast-feeding, said Cynthia Colen, an assistant professor of sociology at Ohio State University and the lead author of the study.

“I’m not saying breast-feeding is not beneficial,” Colen told the media at the time of the study’s release. “But if we really want to improve maternal and child health in this country, let’s also focus on things that can really do that in the long term — like subsidized day care, better maternity-leave policies and more employment opportunities for low-income mothers that pay a living wage, for example.”

For me, formula has been so vilified that I felt as if I was constantly explaining my situation.

While I would have loved to breast-feed — it’s cheaper than formula, for one — and I was genuinely happy for friends of mine who enjoyed it, I found the study a huge relief.

I sent it and a few other stories that dared to question the idea that breast-feeding was bliss — such as the Web site Jezebel’s irreverent essay and Hanna Rosin’s myth-shattering Atlantic Monthly article “The Case Against Breastfeeding” — to friends, both breast cancer survivors and a group of women who might appreciate the notion that breast-feeding may actually be overrated.

Not everyone wanted to know. When I told one friend about the study, she listened and then said, “I have some of my frozen breast milk in my freezer. I could bring it over for Lincoln.”

I know she was only being nice, but . . . yikes!

But some friends found it liberating. Not everyone judged me for feeding my little guy formula. In fact, after I sent around the study, some women shared that they wished they could stop breast-feeding so they could leave the house for more than three hours at a time. Or so the father or grandparent could give a bottle. Or because it hurt. Or because they needed to work and couldn’t spend long breaks pumping. Or because they adopted their child and couldn’t. Or because they just didn’t want to.

As Jezebel’s Tracie Egan Morrissey wrote: “What those lactivist [expletive] conveniently forget to tell people — in their ongoing campaign of castigating bottle-feeding mothers as unnatural and ignorant, masking their concern-trolling as “support” — is that breastfeeding, for many women, is an incredibly painful, almost traumatizing endeavor. It was all so miserable and I associated that misery with my new baby, whom I secretly resented.”

Whispered confessions

Others literally lowered their voices to a whisper, confessing as if they had committed a crime that they supplemented breast-feeding with formula.

Why did they feel they had to whisper? In many ways, it reminded me of the stigma that comes with having a C-section.

I even found myself offering facts: Formula actually grew out of a 19th-century effort to end infant mortality, I said proudly. How did this happen? I had become the badass leader of the “no-I-don’t-breast-feed-because-I-had-CANCER-so-back-off” club.

And I pointed out how I loved that my husband could give Lincoln the bottle and bond, especially during those feedings at 3 a.m.

And I told them about Suzanne Barston’s book “Bottled Up: How the Way We Feed Babies Has Come to Define Motherhood, and Why It Shouldn’t,” and her Fearless Formula Feeder blog.

Barston started blogging after struggling to breast-feed, “despite latching issues . . . nerve damage in one breast, severe and sudden postpartum depression, a traumatic birth, jaundice” and other difficulties. After that barrel of laughs, she became a formula-feeding mom, her Web site says.

I also referred friends to Rosin’s article in the Atlantic, which concludes: “Medical literature looks nothing like the popular literature” that heavily promotes the positives of breast-feeding.

The irony, of course, is that women who breast-fed in the 1970s say they were judged for being crunchy Earth mothers by those who gave the bottle. Now they are considered mainstream and judging formula feeders. Can’t we all just get along?

Today I’m back at work, and sometimes I miss those maternity-leave baby yoga classes. I’m especially grateful for one thing I was told by the instructor, who overheard the fellow mommy-and-me-yogi lecturing me about breast-feeding.

“In a few years when they’re in preschool, you will never have to talk about breast-feeding again,” she said. “So don’t even think about it. Enjoy your baby. You earned it.”