One of the most contentious attachment practices is co-sleeping, or allowing babies to sleep in the bed with parents. Never mind warnings about accidentally smothering or suffocating a slumbering infant, Freud would likely be more worried about this practice's psychosexual ripple effects [source: Belkin]. To clarify, co-sleeping is generally geared toward infants, whereas the Freudian phase it would impact the most takes place between ages 3 and 6 years old. It's in that latter, so-called phallic phase that boys and girls supposedly develop subconscious sexual attractions to opposite-sex parents, along with concurrent rivalries with same-sex parents. Boys, therefore, encounter the Oedipus complex, in which their mothers become the apples of their young eyes, and girls battle the Electra complex of paternal adulation. Sleeping in the marital bed, from Freud's perspective, would only aggravate those psychologically confusing conflicts, deepening those love-hate impulses and causing neuroticism down the road [source: Sullivan].