The first time I considered giving up my baby, Dan, I was lying alone in bed. It was midnight, my children were asleep and my husband, a serviceman, was deployed away from home. I was so taken aback by my thoughts that I sat bolt upright, ran to the bathroom and splashed cold water on my face. It was dark, but I could see my silhouette in the mirror and I stared to see if I was looking at a demon instead of Dan's mother.

I ran to Dan's room, afraid that he was already gone. But he was there, lying on his Thomas the Tank Engine sheets, sucking his thumb and breathing evenly. I caressed his cheek with two fingers and he exhaled. "I love you, little man," I whispered and kissed his forehead, swallowing down the knot in my throat. I went back to my room and sobbed into my pillow.

Dan was my adopted son. He's a little boy from South America who became part of my family several months before that frightening night. He arrived through Miami international airport on a Monday afternoon and I was so anxious that on my six-hour drive to pick him up, I dug my nails into the steering wheel leaving marks I can still see today. I couldn't contain my excitement.

I had wanted to adopt for a long time, even before I met my husband or had my biological daughters. I've always wanted a large family, like the one I grew up with in Italy, and I love the chaos and liveliness of many kids.

I did lots of research on adoption, including attachment issues, and went through a thorough screening process with social workers. We were approved, and began the long wait for a referral. When they told us about Dan, I was ecstatic and convinced that I'd be able to parent this little boy, the same way I had done with my biological daughters.

Our paediatrician diagnosed our son, when he arrived in the US, with some expected health problems and developmental delays. His age was not certain – he had been found by the side of a road – but the doctor estimated he was a little younger than one year. Dan lacked strength in his legs and had a completely flat head, from lying in a cot so many hours a day.

But the physical or developmental issues weren't the real problem. Five or six months after his arrival, I knew that Dan wasn't attaching. We had expected his indifference towards my husband, who was deployed away from home for most of this time, but I worried that our son should have been closer to his sisters, and especially to me.

But Dan's attachment problems were only half the story. I also knew that I had issues bonding with him. I was attentive, and provided Dan with a good home, but I wasn't connecting with him on the visceral level I experienced with my biological daughters. And while it was easy, and reassuring, to talk to all these experts about Dan's issues, it was terrifying to look at my own. I had never once considered the possibility that I'd view an adopted child any differently than my biological children. The realisation that I didn't feel for Dan the same way I felt for my own flesh and blood shook the foundations of who I thought I was.

I sought help and we had some attachment therapy to strengthen our relationship, but still I struggled. One day I was on the phone with Jennifer, our social worker, when suddenly I blurted out that I couldn't parent Dan, that things were too hard.

As soon as I said these words out loud, a flood of emotions washed over me, and I sobbed. Jennifer didn't say anything, she waited patiently, and when I had nothing left, she asked me to start from the beginning. We talked about my family; about the problems my husband and I were having with Dan and, as a result, with each other; about the girls and their partial indifference toward Dan; and about some of my son's specific challenges.

For the next several weeks, Jennifer and I spoke daily. She mostly listened and told me to focus on Dan's future and wellbeing above everything else.

My thoughts and emotions were disjointed. One moment I was determined to keep Dan because I loved him. An instant later, I realised that I wasn't the parent I know I can be, and that I should place Dan with a better family, with a better mother.

As I wrestled with these demons, things remained very tense; whenever my husband was home we fought incessantly. Then early one morning Jennifer called, and told me that she had found a great family for Dan. They had seen his pictures, heard his story and fallen in love with him. The mother, Samantha, was a psychologist, and the family had adopted another boy with similar issues a couple of years before.

I spoke to Samantha and her husband a few times on the phone and instantly felt comfortable with them. We decided that she should come down to meet Dan by herself, to ease the transition. The decision was final. Less than two years after he arrived, Dan would leave my home.

While waiting for Samantha to arrive, Jennifer helped me to talk to my kids, and other family members, but most importantly she held my hand when it came to speaking with my son. I explained to him that he'd be joining his new family and that we loved him very much – that he had done nothing wrong. I don't know how much he understood.

For my first meeting with Dan's new mum, I was a wreck. I dressed him in one of his cutest outfits, strapped him into the car seat and took off to meet Samantha at a nearby McDonald's. The ride was short, but each time I approached a traffic light, grief assailed me, and I turned around, determined to head back home. The five-minute trip turned to a 30-minute journey, and when I finally made it to the car park, I was frazzled. My hands were shaking and my mouth was dry. Samantha recognised us as soon as we got out of the car, and rushed over. Her eyes lit up the moment she approached Dan, and she lowered herself to his height to hug him.

Over the next few days, Samantha and Dan got to know each other. Finally, it was time for him to leave with her. That morning, I awkwardly let her into the house and willed time to stop. Hands shaking, I handed her Dan's bag and some of his favourite toys. My daughters were watching SpongeBob SquarePants and said goodbye to their brother almost nonchalantly, as if he was just going out for a bit and would soon be back.

I opened the front door of my home in slow motion. It felt heavy and my feet stayed glued to the ground. Samantha told me she would give me a few minutes alone with Dan and walked to her car. I knelt and pulled Dan close, desperate to impress an indelible memory of my son on me, and me on him, inhaling his scent, feeling his soft skin and touching his hair. In our last moments together, I stared into his eyes and told him I loved him and that I had tried to do my best.

His new mum would love him so, so much; my little man would be OK.

He didn't cry, he stared back at me, then looked to Samantha and asked for more juice. I was too overwhelmed to utter another word, but Samantha squeezed my hand and reassured me that Dan would know I had loved him and that I had done a good job.

Over the next few weeks I felt a mix of emotions – desperation, relief, sadness, guilt, shame, and acceptance. After a couple of months at Samantha's home, I learned that Dan was doing well and adjusting to his new life. He was struggling with some issues, but I know that Samantha and her husband are the best parents Dan could possibly have. The fact that he also has a sibling who has dealt with similar issues has made the transition easier.

My husband had originally asked me not to write about Dan, because I would only open myself up to criticism. But I wrote this because Dan taught me a lot about myself and about parenting, and because I hope that by sharing this experience others can feel less alone in their failures. I have more compassion for the mistakes we make as parents and I'm far less willing to point the finger at others' difficulties.

I don't have anything left from Dan's time with us. Samantha didn't want Dan's clothes – I think she preferred to make a fresh start, so I donated everything to the Salvation Army. We don't have Dan's pictures around because my husband thought it would be too difficult, but in my wallet I carry a small close-up photo of his face. When I think about him, I take it out and look into his big, dark eyes as a deep, endless sadness fills my heart.

Thank you, little Dan, for all that you have been to me, to us. Despite my failures, I loved you the best way I could, and I'll never forget you.

Postscript This account first appeared on a blog several months ago. Since then my family has come under intense public scrutiny in the US, where we live. I knew there would be a lot of criticism, but my intention was to share a very personal experience. I don't mind the criticism, but I have been surprised by the degree of hatred displayed towards me and my family. Some readers have made fun of my children's looks.

There have been many positive comments, too, and I'm thankful to the many families who shared their own painful stories with me.

I do not regret writing about Dan. I shared this experience because when I saw my own shortcomings, I was humbled. We all struggle with our weaknesses, too often alone.

Dan's name and some other details have been changed to protect his identity. Anita Tedaldi's blog is at ovolina.com

When love is not enough

The British Association of Adoption and Fostering (BAAF) estimates that one in five adoptions break down, although children who are "handed back" are usually older. The younger the child, the lower the chance of the placement breaking down. A study by the Maudsley Hospital in London found a breakdown rate of 8% after one year and 29% six years later. On average, adoptions that broke down did so 34 months after placement.

Despite the negative publicity that overseas adoption has attracted in recent years, there is no evidence that they are more likely to break down than domestic placements. Many studies have concluded that international adoption has, for the most part, been very successful, including for children who have spent their early years in institutions.

Children placed in stable, loving families, show a great capacity for catch-up – although a great deal depends on support from the wider family and adoption specialists, and the extent to which the adopters mix with other people from the country they adopted from.

The sad fact is that in many states of America, where Dan was adopted, this combination is less likely to be recognised as essential, despite the fact that overseas adoption tends to be far easier than it is here. Also undoubtedly contributing to Dan's adoption breakdown is the fact that for a minority of the most deprived children, major problems – especially in the area of attachment – do not go away, regardless of how much help, support, stability and indeed love, is provided. Kate Hilpern

• This article was amended on Monday 23 November 2009. A sub-heading on the original suggested that when the author adopted a baby boy, she already had all her five daughters. This has been corrected.