Conclusion
In conclusion, utilising close to 1500 singleton term births from an ART cohort, our results demonstrate that maternal or paternal overweight and obesity increases infant birthweight independent to the BMI of the other partner, with no additive effects seen if both parents were overweight or obese. Further studies are warranted in both ART and general population cohorts to support or refute our findings. Our results highlight the notion for family unit preconception health initiatives.