Paulina Gretzky, the 26-year-old daughter of hockey legend Wayne Gretzky, gave birth to her son, Tatum, five months ago. A photo she posted to Instagram on Wednesday shows that the model has already reclaimed the fit physique she had before pregnancy.

What is Gretzky's secret? Is it diet and fitness, or good genes?

Judging from this picture of her 54-year-old mother, Janet Gretzky, who is the mother of five and grandmother of one, good genes play a major part in Paulina reclaiming her pre-pregnancy body: