Is buying foreign bonds indenturing someone elses children?

Bonds are loans, but they are your end of the loan - they are a promise by a governement, or the central bank depending on the country, to pay the bondholder at some time in the future. What they promise is to pay the face value of the bond plus an interest.
You see various reasoning about that interest. Why are you getting interest, really? One reason that is that you take a risk with your money - but very few countries are Greece. But bonds are supposed to be the safest financial instruments around. OK, so the interest is lower than that of riskier investments. But since all governements are dependent on lending money, they do not want to put off the people who have lent money to them, but rather they want them to lend the money to them again when they have to pay it back. So part of the reason for the interest is to keep the lenders happy.
But since bonds are assets, the interest adds to the assets of the lender - the bondholder. If the bondholder is a pension fund, the interest - that the the governement pays - goes to pay to the people who have put in money into the fund (or who have earned retirement rights in some cases). In other words, the governement retirement fund pays people their pensions out of money it recieves from the governement. That's right, it is actually a tax which goes to the retirees.
But there are other people who own governement bonds. Banks are one what do banks do with their assets? They use them as security for lending money. Which they charge more in interest for than the security. And what happens when they lend money? They get a security that they can use to lend more money.
This may look like magic but it is just bookeeping. Like all money. Bonds are promises, so is money. But money is valid now. Bonds will pay in the future.
So what you do when you buy bonds in your own country is that you buy a promise from the governement to pay you in the future. Probably they will have to raise taxes to do so, since most countries are running a deficit and the economy of most big countries is not growing. That the economy is not growing means that there is less money to lend to the governement, so they have to pay back some of the principal in addition to the interest. Which decreases their ability to do other things, like pay salaries and pay into retirement funds.
If you buy bonds in a different country, you buy a promise by the governement of that country to pay you in the future. That may be a good if you live in Greece and buy German bonds. Since those countries are most likely not running a surplus, they will have to raise taxes to pay you.
In the future. After the next election.