It's just a tad blurry to get a good idea, if you can get a focused image on the horizontal line just below the first two book lungs that'd be superb. However, if I have to guess on this, I'd say male due to the dark patch just above the furrow - IIRC, it is indicative of the gonopore, responsible in the aid of making sperm webs.
@Ztesch Still a possibility it's female since I can't see it as well as I'd like. If you wait for a molt, it'll be VERY obvious whether or not it's a male or female - the spermatheca on a female's molt are obvious from a mile away. Unfortunate they grow so glacially, really want to know if I'm correct on the guessed sexes of my own pair.
@boina Well, some vague idea is better than none - I'm absolutely certain ONE of them is male, but I'm afraid that I'm too biased in wanting a female to be able to try and guess on the other. I'll drop them in your inbox when I can, I'm marooned at work for another three hours unfortunately