Yes. Obesity can affect fertility in both males and females.

Obesity and Male Infertility

According to a study headed by Dr. Eric M. Pauli of the Pennsylvania State University College of Medicine, males who suffer from obesity also suffer from hormonal imbalances and irregularities that contribute to their fertility problems.

The study found that obese males had lower testosterone, luteinizing hormone and follicles stimulating hormone levels. Apart from these hormonal irregularities, obese males were also found to have lower libido levels and higher chances of suffering from erectile dysfunctions.

Obesity and Female Infertility

Studies show that obese females are highly at risk for reproductive problems. According to statistics, severely obese females have a forty-three percent decreased chance of getting pregnant.

Most studies propose that female obesity causes problems with ovulation, therefore making them unable to conceive. A recent study however, headed by Dr. Jan Willem van de Steeg of the Academic Medical Center in Amsterdam, shows that there are some obese women who still ovulate and have regular menstrual cycles, and yet are unable to conceive. This shows that regardless of whether the female ovulates or not will still cause her to be infertile if she is obese.

Another reason why female obesity affects infertility is because it is believed that chronically high insulin resistance levels, which is common in obese individuals, affects a female's ability to conceive.

However, a recent study shows that it is not only high insulin resistance levels that contribute to female infertility but it is also the effect of high insulin resistance levels on the pituitary glands which cause women to be infertile. This new study proposes that treatment for obese and infertile females should not only focus on lowering insulin resistance levels, but on decreasing the pituitary gland's sensitivity to insulin as well.