Here is what I know. I have an extremely healthy daughter who is now 36. She has been a runner and a soccer coach since she was a teen. She runs maybe 8 to 14 miles a day after her day job as a social worker and right before she goes to soccer. She doesn’t eat much in the day at work except snacks like a protein bar or some addictive favorites that aren’t good for her( goldfish and DOTS pretzels). She drinks a ton of water! Her bloodwork is perfect! She hasn’t had a period since probably before she was 21. If she ever gets one she wouldn’t probably have more than a spotting. Like you I worry because girls who don’t get their periods are more likely to develop bone issues later in life. We have periods for a reason. I think it is unlikely it would interfere with your daughter’s ability to have a baby . As a child I was not a runner but didn’t get my period very often most likely because I didn’t eat well, and I got married and had four biological children. My daughter is adopted from a Chinese orphanage. Bottom line I wouldn’t worry about the baby thing - but the bone thing is a concern ! Irene5