Humans do not have purely seasonal breeding patterns, though fertility shifts can occur.

“Seasonal rhythms have a number of effects but humans are not purely seasonal breeders. Unlike a lot of animals, we breed all year long. In fact, there's a preponderance of September babies in my life, not actual babies, because they're born in September which means that they were conceived in December, without knowing the details we can fairly assume that. And December, at least in the Northern hemisphere at days tend to be shorter and nights tend to be longer. So clearly humans aren't seasonal breeders but there are shifts in breeding and fertility that exist in humans, but also much more strongly in other animals.”