A recent study conducted by researchers at the University of Passo Fundo in Brazil suggests that breast symmetry may be a more significant factor than size in perceived breast appeal. The study, published in the Brazilian Journal of Plastic Surgery, surveyed 239 medical students to determine preferences for various breast shapes and proportions.

Participants were shown images representing three different ratios between the upper and lower portions of the breast: 40/60, 50/50, and 60/40. The findings revealed that the 50/50 ratio, indicating an equal distribution between the upper and lower poles, was preferred by 61.1% of respondents. A more voluminous upper half, represented by the 60/40 ratio, was favored by only 10% of participants, while the 40/60 ratio garnered 28.9% of preferences. This contrasts with a 2023 New York University study that indicated moderate-sized breasts with greater upper-pole volume received higher attractiveness scores.

Beyond proportions, the Brazilian study also explored preferences for nipple placement and the size of the areola and nipple. Nearly 60% of the surveyed students preferred a centrally located nipple. Furthermore, 83.68% of participants favored a small areola and nipple size.

"The results demonstrated a preference for symmetry patterns compared to those with some pole deviation or angulation," the researchers stated in their findings. They also noted that preferences were largely consistent across genders, suggesting a unified perspective on breast aesthetics, with a "predominant appreciation for harmonious proportions."

The researchers hope these findings can assist plastic surgeons in understanding patient desires and refining surgical techniques to prioritize symmetry. This aligns with observed trends in plastic surgery, where an increasing number of patients are reportedly seeking less exaggerated results and opting for smaller implants, a shift noted by some surgeons from a previous decade's demand for significantly larger enhancements.

Separately, a 2024 study from Texas A&M University proposed that larger breast sizes may be associated with increased instances of verbal and indirect aggression from other women. Researchers in that study hypothesized that women with larger breasts might be perceived as a threat, potentially triggering competitive psychological mechanisms among women, particularly in the context of mate selection.