Would you like your child to be an Olympic athlete one day? You would need to start the training early. It starts in the womb. While going 90 miles an hour down ice slopes, doing freestyle flips and somersaults of mountains on skis or snowboards or doing triple axles on the ice may not be a good idea during pregnancy, exercise during pregnancy is. Fit moms make fit babies. Studies show that exercise and, more specifically, more and more intense exercise during pregnancy produces children with advanced coordination, balance, strength, speed and endurance, creating superior sports performance. 
Starting athletics well before pregnancy helps even more, as well trained moms can be more active in pregnancy. Higher volume exercise levels also help reduce complications in pregnancy and facilitate a speedier return to physical activity and athletic competition post-pregnancy, according to a Norwegian study. 
Speaking of Norway, a Norwegian region of Trøndelag3 seems to prove these studies right. Norway has prior to Sochi won 303 winter Olympic medals, of which 107 were gold. This is more winter Olympic medals than any other country, and Norway is tiny with only 5 million inhabitants. Only 400,000 live in Trøndelag in the middle of Norway, but the area has produced over 20 percent of Norway's Olympic medals. At the 2010 Vancouver Olympics they took 8 of 9 of Norway's gold medals. It is a place with short summers and long winters, that exists mostly on farming requiring year round hard work outdoors. Although all Scandinavian countries enjoy cross country skiing, this region in particular spend more time outdoors working, enjoying the wilderness, and they cross country ski everywhere, no matter how cold it is. This outdoorsy, way of life has produced generations of mentally and physically strong and fit Olympic athletes that come back to Trøndelag to work on farms enjoy skiing and raise families, producing more athletic children.
In addition, watching the Sochi Olympics, you may have noticed quite a few of the athletes from other countries' are also following in their parents Olympic footsteps.
Perhaps this years Olympics will inspire more women and men to get fit prior to parenthood. Epigenetically, fitness begets fitness.
1 J. M. PIVARNIK, HEATHER O. CHAMBLISS, JAMES F. CLAPP et al. Impact of Physical Activity during Pregnancy and Postpartum on Chronic Disease Risk. Amer. Col. Of Sports Med 2006: 989-1006.
2 KRISTIN R. KARDEL Effects of intense training during and after pregnancy in top-level athletes. Scand J Med Sci Sports 2005: 15: 79-86.
3. How Norway Scores so Much Gold. Ellen Emmerentze Jervell WSJ Feb. 2014