Bog Child has received general critical acclaim for its delicate balance of reality and optimism. Although it is set against a gruesome background of violence and conflict, it manages to convey a message of hope for the future. Writing for The Independent,Brandon Robshaw says the book

doesn’t pull its punches, but ultimately the message is of hope, forgiveness and reconciliation.

Meg Rosoff of The Guardian agrees:

With...conflict comes sadness, an undertow of psychological darkness, but also a belief in love's power to redeem the human soul, and even, perhaps, the future of mankind.

Both critics emphasize the parallels between the stories of Fergus and Mel, which revolve around young heroes who need to find ways to unite communities in the midst of political conflict.

According to Robshaw, Bog Child is

a spectacular demonstration that books for younger readers can handle the big themes.

Siobhan Dowd treats her young readers with respect; she assumes they can handle realistic conflict and grief. Although she punctuates the grief with humor and romance, these lighter scenes enhance the story’s realism and underscore the complexly optimistic side of Dowd’s message. Although Dowd clearly feels deeply about the importance of life, she does not belabor her moral points. Rather, she lets each character embody one realistic point of view about life and love, and she allows her readers to draw their own conclusions.

Nicolette Jones of The Sunday Times points out that Bog Child presents a world where characters have to struggle to figure out morality in a world “of transgressions, large and small.” Dowd’s world is textured and complex, a place where life and death choices can exist side by side with the flirtations of first love. She manages to portray both with admirable psychological realism.

Her sentences, written in a modern Irish vernacular, have a deep, musical rhythm. Rosoffpraises Dowd for her beautiful prose:

Dowd appears to be incapable of a jarring phrase or a lazy metaphor. Her sentences sing.

Bog Child was published in 2008, shortly after Dowd died of cancer at age 47. Many critics speculate that the story is, in part, a dying author’s manifesto of her love of life. This interpretation fits well with the ending of the book, when Fergus, having escaped self-sacrifice, revels in the idea of a bright future.

He’d years of the changing to come. The studying, the books, exams, arguments, theories. The jokes and pints, laughter, kisses and songs. Life was like running, ninety percent sweat and ten percent joy.