Those women who are pregnant, have been pregnant, or think they may one day be pregnant, would do well to check out one of the most advanced set of images I've seen to date showing what is inside the woman from the 6th week onward. (link) It's not just a lump of tissue - its a tiny person developing and growing in ways that are normally impossible to observe.
And though we know a lot more about when it happens than did our ancestors, even now the growth of children in the womb is quite a marvel to observe.
Ecclesiastes 11:5 As thou knowest not what is the way of the spirit, nor how the bones do grow in the womb of her that is with child: even so thou knowest not the works of God who maketh all.
H.T. Melinda at Stand to Reason for bringing this to my attention (link).