Table 1.

Summary of studies that found altered fetal/offspring outcomes in response to singular (maternal or paternal) or combined parental exposures.

Factor	Singular/Combined	Major Outcomes/Findings	Species	References
Parental obesity	Paternal alone	Minimal impacts on seminal quality. Some studies indicate links between the Kisspeptin signaling pathway and obesity-induced male infertility Obesity may disturb early embryonic cell cycles kinetics, seminal/spermatozoal biomolecular composition, diminish reproductive performance and increase sperm oxidative stress	Human/Rodents	[20,21,22,23,24,25,26,27]
	Maternal alone	Maternal obesity been associated with high rates of meiotic spindle abnormalities, defective mitochondria, increased levels of reactive oxygen species, dyslipidemia, perturbed follicular fluid composition and oocyte quality	Humans/Mice	[28,29,30,31,32,33,34,35,36]
	Combined parental	Combined parental obesity leads to impaired post-fertilization development and offspring health, e.g., increased risk of birth defects, elevated weight gain in postnatal life and metabolic disorders in adulthood	Humans/Mice	[53,54,55,56,57,58,59,60,61,62]
Advanced parental age	Paternal alone	Perturbed growth and development, dysregulated immune cell profiles, increased risk of autism spectrum disorders and impaired neurocognition	Humans/Mice	[66,67,68]
	Maternal alone	Programming effects similar to those observed in advanced paternal age studies	Mice	[64,65]
	Combined parental	Reduced fecundity and compromised neuro-development	Humans	[69,70]
Parental Exposure to Environmental Pollutants	Paternal alone	EDCs disrupt the hypothalamic-pituitary-gonadal axis, thus compromising sperm/semen quality, conception potential and embryonic development	Humans/Rodents	[72,73,74,75,76,77,79]
	Maternal alone	EDCs disrupt the hypothalamic-pituitary-gonadal axis, affecting oocyte’s structural and functional integrity and thus compromising fertilization potential	Humans/Mice/Cattle	[82,83,84,85,86,87,88,89,90,91,92]
	Combined parental	Adverse pregnancy outcomes, e.g., altered morphometry of fetus/embryo, impaired growth	Humans	[78,80,81,93,94,95]

EDCs: endocrine-disrupting chemicals.