Report: Baby not covered under family's Obamacare plan?

How does this happen?  Via the NYPost:

Long Islander Cornelius Kelly found it would be no problem to secure a family plan for his wife and three older kids through New York’s health-care exchange, but his 18-month-old daughter was out in the cold. The baby would need her own insurance policy. ...

Kelly, 41, and his wife, Jennifer, 42, are self-employed and have always had to buy their own insurance. Kelly runs a title insurance business in Westhampton, and his wife is a pediatrician in private practice in Miller Place. “I initially went on with a lot of optimism,” he said.

Kelly said none of the plans offered out-of-network coverage, which was something he wanted. But even worse, they only covered his three older children, who are 3, 5 and 6.

When Kelly called a representative, he was told his daughter had to be 2 before she could be covered under a family plan. He would have to buy a separate plan for her, at monthly premiums that ranged between $117.21 and $369.31. The cost would be on top of a family plan with premiums ranging from $810.84 to $2,554.71 a month.