Right now - the actual sperm and egg are still needed. So, a man does need to donate his 'goods' for a lesbian couple to use, and an egg and surrogate still need to be used for men to conceive.
BUT, from what I can recall, and unfortunately I can't provide articles on it (given the short amount of time I have, etc) - but I do remember an article a while back about some research in the ???UK where they were looking at using a woman's stem cells to produce sperm.
The theory seems to make sense - stem cells are where ALL cells in the body start from, so in theory manipulating these to become sperm cells rather than say skin or ovum cells could be done....in theory. Which would mean that two woman, with the assistance of medical technology, could become the biological parents of a daughter - daughter as the 'sperm' would be all X's, due to the stem cells being from a woman.
There is a movie about it in theory, the Baby...something..(gah!), but I've actually read an article in an online magazine on it - granted it's not a medical one...yet!.
Can it be done yet? No. Will it ever be able to be done? Not sure - possibly??
To answer your question - is it still one man +one woman? Simply put - yes.
Does it need the actual sexual act? No.
However, sometimes it's more than one man - when one man does not have the goods - a donor may step in, or be used - just as it can be more than one woman - a donor egg, in the mothers womb...etc etc....but when you get down to it - it's still one persons ovum and one person's sperm isn't it?