Question

The commandment to propagate is from Genesis 9:1.

We are only aware of the Halachic (according to Jewish Law) view on the issue of birth control, and it is as such:

If there is a medical risk in pregnancy, or the woman is mentally ill, or she had a couple children one after the other (year after year) and she is weak and ill from it, then the best is to delay relations till after 20 or so days from the last period. In descending order, the next best, is the pill; then the spray, IUD, diaphragm, and in very extreme exceptional cases of health problems - a condom - (source: "Igrot Moshe" by R' M. Feinstein), E.H. II, 74).

Each case is judged by its own peculiar details. A rabbi who knows the couple in question, should decide whether the given case warrants a temporary allowance for the use of contraceptive measures.

We do not see it all as a problem of over-population. In fact, millions of Jews were killed 60 years ago (and are continued to be killed in the terrorist actions, here in Israel). We have a duty to replenish these lost Jewish souls.