Do you believe that life starts at the moment of conception?

It depends on what you mean. "Life" is a very ambiguous term. Technically, at conception, when the sperm and egg cell fuse together, this is the beginning of a "life". But it's no more alive than one of your skin or heart or liver cells. It has all the life and consciousness of an amoeba.

Also, it's important to realize that at conception, there is only one "life", a single cell. This is true even in the case of identical twins/triplets/etc. All of them come from a single original life - they're natural clones, literally. "Life" didn't start for any of them, either in the biological or "religious" meaning, until after the very early embryo split off into multiples. And one thing scientists have known for a very long time is that we can artificially make this process happen, reliably. This is different from cloning adults, which is a lot harder, since there we need to make existing adult cells revert to an undifferentiated state like embryonic cells. But, at any time, with their saved embryonic stem cells, we can easily clone using those cells, making any number of identical "siblings". Is "life" beginning then? Even outside a laboratory, many fertility drugs dramatically increase the chances of spontaneous splitting into identical siblings. Life in any real sense we mean it can't begin at conception.

I would argue that the only "life" that we're interested in is actually life that is conscious. For that, we can see the embryo's development. The first neurons, cells in the brain, spinal cord, and other nerves, appear after 3-4 weeks. At this point there is less "consciousness" than there is in a jellyfish, which we gladly kill; and a goldfish is vastly more conscious than the emrbyo. At about 3 months though, it becomes clear that the brain is developed enough that there is significant consciousness. At 5 months, many unborn babies can actually survive outside of the womb if premature, with modern medicine. Most women, who give birth at full term, at about 9 months, have been carrying a child that could have survived, with only moderate difficulty under the right conditions, or as many as three months.

I guess what I'm saying is that the broader question of "when does life start?" is ambiguous. There is no exact point at which we can pinpoint the emergence of consciousness, and it does vary slightly from fetus to fetus, to complicate things. Before consciousness arises, we're looking at a slimy sub-jellyfish, and after the first simple consciousness arises, we're on a slippery slope of murder if we abort, becoming more and more wrong as the fetus matures. The biggest problem with the whole question is the definition of "life", what we mean by it in this context. We're not allowed to say "soul", because no one can measure a soul, so it has to be something measurable.

Also, as an aside, biblically, there's about equal support for "life begins at conception" versus "life begins at birth" - maybe a bit more for "birth". Jews believe it's at birth, and Christians generally at conception. I'm not sure about other faiths. But really, as I hope I demonstrated above, it isn't nearly so black and white as all that.