Some women start getting more interested in children in their late thirties and early forties when they start hearing their biological clocks ticking down. You could wait and see if this happens, but there’s no guarantee.
This idea that she has to take a year off is probably just an excuse. There is plenty of evidence that children in daycare from the age of three months do just as well or even better than children who are with stay at home parents. We put both our children in daycare at three months. My wife felt a little guilty about it, but a decade later, she never even thinks about it. They are, of course, the most special children ever in the whole wide world, but that’s neither here nor there! ;-)
Your wife is gaining a lot of prestige in her job, and she doesn’t want to give it up. She believes there is a “Mommy track” and she doesn’t want to be shunted over onto that track. This may or may not be true. You might research it. It could be that women are doing just find career-wise in the medical profession even if they do have a child or two.
But I think these are all just excuses. I think she really doesn’t want to have a child and never will. I don’t know her, of course, so my feeling isn’t worth a hill of beans, but I’ll give it to you anyway.
So, how badly do you want children? Badly enough to leave this marriage? Badly enough that if you stay in the marriage you’ll be forever resentful?
Most of us have a strong urge to have children. If we didn’t have it, the species would die out. You have that urge. She doesn’t. You, however, would be satisfied with an adopted child, so that means you want to parent more than you want to pass on your genes. She clearly doesn’t want to parent. She’d resent the child no end, even if you adopted.
If you want to be a parent, I think you have to get out of this marriage. It will be no guarantee, but at least you will be trying. If worst comes to worst, you could adopt on your own. But, unless she honestly changes her mind, and comes to truly want a child, this will always be between you, and there will be resentment on both sides. Not good. Personally, I think your marriage is over. But again, I don’t know shit about you, so my advice isn’t worth the pixels used to display it. That’s what you get for asking a question like this online.