Although Birthday Girl is a romance, it portrays serious issues such as the impact of a neglectful upbringing. Both Pike and Jordan deal with less-than-ideal parenting in different capacities. Jordan’s mother left the family when Cam and Jordan were children, and their father, Chip, is not a present parent. Jordan frequently refers to the fact that Chip is known around town for his addiction to alcohol and his spendthrift habits. Chip’s wife and Jordan’s stepmother, Corinne, treats Jordan with apathy.

While Pike is a responsible father, his ex, Lindsay, is lax. Cole might love Lindsay very much, but Pike suggests that she often ignored Cole as a child, preferring to party rather than take care of her son. Because of Lindsay, Pike has had to be the overtly responsible parent, ignoring his personal happiness in the process. In this way, the novel suggests that neglectful parenting impacts not just children but also parents and adults.

Jordan and Cole have troubled relationships with themselves and others because of the neglect they have experienced. At the beginning of the novel, Cole is depicted as irresponsible, thoughtless, and unfocussed, often leaving Jordan to her own devices or even in dangerous situations, such as when he sends Jay McCabe to pick her up.