for science pdfs the best that I have found is Papers on an iPad
zoom in on figures in full color, pdfs organized the same way as on the desktop.......
goodreader and pdfreaderpro are ok but lack the organization that Papers has
in many species the female is heterozygous for the sex chromosome not the male- the ZW system in some insects is a prominent example
Time Lords may be one of these species so that a clone of a male could be female