08/16/2007 AT 04:00 PM EDT
As the custody fight between Britney Spears
and Kevin Federline
gets down and dirty, the pop star's parenting skills are going under the microscope, PEOPLE reports in its latest issue.
On Aug. 8 Federline's lawyer Mark Vincent Kaplan filed papers requesting primary physical custody of Sean Preston, 23 months, and Jayden James, 11 months. According to Kaplan, "Kevin is concerned that the more time the children spend with him, the more insulated they are from risks."
With subpoenas flying and both sides hunkering down, one woman who worked as a nanny for Spears earlier this year tells PEOPLE, "She's very loving with the kids, well, when she's around and awake.
"When I was with her, she was out partying a lot, and she would wake the kids up when she got home at 3 in the morning because she wanted to see them," the source says. "Then she would sleep in until 1 in the afternoon. It would make my night awful because I would have to try and get them back to bed."
At the moment Spears, 25, doesn't have a nanny – and doesn't want one. "She has two kids under the age of 2 who are doing okay and Britney wants to be that hands-on mom," says a source.
Yet for all the love Spears has for her children, the pop star is "an inexperienced parent," concedes a family friend. "She doesn't have people around her to guide her in being a mother."
For more on Kevin's case against Britney, her bizarre behavior and who's taking sides, pick up the latest PEOPLE.