It's a little harder to dismiss the accusations as Mia Farrow's bitterness at her betrayal, as some did, when those accusations are being made directly and publicly by her daughter:
[W]hen I was seven years old, Woody Allen took me by the hand and led me into a dim, closet-like attic on the second floor of our house. He told me to lay on my stomach and play with my brother’s electric train set. Then he sexually assaulted me. He talked to me while he did it, whispering that I was a good girl, that this was our secret, promising that we’d go to Paris and I’d be a star in his movies. I remember staring at that toy train, focusing on it as it traveled in its circle around the attic. To this day, I find it difficult to look at toy trains....It's important to not get so caught up in defending men that we forget that some men are truly the monsters that the feminists attempt to portray us all as being. Indeed, it is important that we police our own ranks, if only to avoid handing them an easy and effective rhetorical weapon with which to hammer us.
For as long as I could remember, my father had been doing things to me that I didn’t like. I didn’t like how often he would take me away from my mom, siblings and friends to be alone with him. I didn’t like it when he would stick his thumb in my mouth. I didn’t like it when I had to get in bed with him under the sheets when he was in his underwear. I didn’t like it when he would place his head in my naked lap and breathe in and breathe out. I would hide under beds or lock myself in the bathroom to avoid these encounters, but he always found me. These things happened so often, so routinely, so skillfully hidden from a mother that would have protected me had she known, that I thought it was normal. I thought this was how fathers doted on their daughters. But what he did to me in the attic felt different. I couldn’t keep the secret anymore.
This doesn't prove that Woody Allen did it, but his sexually obsessed, neurotic career, and his behavior with Mia Farrow's adopted daughter does tend to lend credence to the charges.