Don't forget that most reputable PA programs require between 500-3000 hours of medical career experience prior to acceptance. If you factor this in, you'll likely find that you can earn an MD/DO in the same time period.
The PA has the advantage that you will post stronger earnings much sooner, but your lifetime earning potential is capped. As an physician, you will be able to work PT and still make roughly the same as a FT PA, depending on your specialty. Additionally, you may decide to work FT again after your kids are raised and you will likely be much more satisfied with your physician salary. Don't forget to factor in the expense of raising your kids, buying a home, funding college, funding retirement, funding vacations, etc into your decision....You may really appreciate the higher earning power of an MD/DO.
Secondly, a PA is just that, an assistant. Are you comfortable entering a career where you will never be the boss? Personally, I want to own and run a small practice after residency. A PA would not allow me to achieve my goal.
Thirdly, there are fields in medicine which offer excellent ability to schedule your career around your home obligations. You can choose to work in one of these fields. Psychiatry is a good example and is not an overly competitive field so you should be able to secure a residency slot if you desire one. You can easily work PT as a Psych attending - days, nights, or weekends. You can also fairly easily start a small practice with low overhead. If you think you would enjoy psychiatry, then you should strongly consider MD/DO. Psychiatry is also one of the less stressful residency programs to complete, from an hours worked perspective. This, coupled with decent earning potential and flexible hours might make it the perfect fit for you.
Lastly, do you want to be a doctor? If so, don't waste your time with PA because you'll likely regret your decision down the road.
PS - don't forget to shadow both professions. It's one thing to think about all the pros and cons of each field, and another entirely to see them first hand.