I've been RNG breeding for quite a while now, but ever since I bred Nidorans. It made me cringe playing the guessing game on which one of the genders I ended up with. As they are different from other pokemon(same for volbeat/illumise).
I really would like to know how do I determine which gender I get from an egg so it wouldn't happen to me again. I would hate to get an Adamant Illumise when I was aiming for Volbeat instead.
I began looking around for answers and on Bulbapedia it is said that it is determined by the last 8 digits of the PID; saying that Nidoran(F) gender digit is 11111110(254 decimal value), and Nidoran(M) is 00000000(0 decimal value). I've already bred Nidorans, but I'm not breeding Volbeats/Illumise at the time so I can't determine how do you determine the value inbetween the 2 sets of bytes.
At first, I guessed that it would be a 50-50 chance, being female if it is below the byte 01111111(127 decimal value) and male if it is above. After looking over several of my nidorans, I quickly realized that it can be false, XD.
Is it determined by looking at all 4 gender ratios? But I know that this can't be completely true as I have received a Nidoran(F) from choosing an egg PID that said that all gender ratios are male.
Has anyone else done reseach with this? I would appreciate it a lot if someone could help me solve this puzzle...

Click to expand...

So I have began some research to the best that I can on breeding Nidorans. and the results from breeding them varies. Below, I put down any information need if someone wanted to copy my experiment.
I bred using the parents Nidoran(F) and Nidoran(M). I did NOT skip any eggs; they did come up with the predicted nature/ability from RNG Reporter. I made sure to breed at least 3 of each of the possible gender ratios: M/M/M/M, M/M/M/F, F/M/M/F, F/M/F/F, and F/F/F/F.
Code:

[LEFT]Pokemon Platinum
ID: 30247 SID: 28265
Seed:2F080260 Date: 11/02/2010; 08:09:16
Delay: 598[/LEFT]
[LEFT]Egg Frames: PID: Gender Ratio: Nido's gender: byte from PID that determines gender & dec value: LID and value
1: FA5E697F: M/M/M/F: F: 7F or 127: 697F OR 27007
2: BF24D6BD: M/M/M/F: M: BD or 189: D6BD OR 54973
3: E53F7B46: F/M/M/F: F: 46 or 70: 7B46 OR 31558
4: 1A37BC5A: F/M/M/F: M: 5A or 90: BC5A OR 48218
5: D8C8374C: F/M/M/F: F: 4C or 76: 374C OR 14156
6: FCBD3CFB: M/M/M/M: F: FB or 251: 3CFB OR 15611
7: 01423639: F/M/F/F: F: 39 or 57: 3639 OR 13881
8: 841837D7: M/M/M/M: F: D7 or 215: 37D7 OR 14295
9: 4C1FC31B: F/F/F/F: M: 1B or 27: C31B OR 49947
10: D2B5E813: F/F/F/F: M: 13 or 19: E813 OR 59411
11: 09099A57: F/M/M/F: M: 57 or 87: 9A57 OR 39511
12: 5A455EE0: M/M/M/M: F: E0 or 224: 5EE0 OR 24288
13: 8B10AC06: F/F/F/F: M: 06 or 6: AC06 ORR 44038
14: 83122A1A: F/F/F/F: F: 1A or 26: 2A1A OR 10778
15: B1D690E5: M/M/M/M: M: E5 or 229: 90E5 OR 37093
16: 10D55D53: F/M/M/F: F: 53 or 83: 5D53 OR 23891
17: 80F0DB32: F/M/F/F: M: 32 or 50: DB32 OR 56114[/LEFT]
18: 10C293A1: M/M/M/F: M: A1 or 161: 93A1 OR 37793
At first, I believed that what determines the gender is if the decimal value is divisible by 9; which would give you a Nidoran(M) until I ended up on egg #10 which given me a prime number(with more nidoran(M) eggs that ended up with a different number that isn't divisble by 9). After hatching all 18 eggs, I then looked at the LID to see if it would be something similar to how wurmple is determined to evolved into Silcoon or Cascoon. This also is inconclusive, but it seems that the LID value for the male Nidorans have a greater number than the female nidorans. At least in this experiment.

EDIT: From Serebii's website(I know it's bad to quote from their website half the time, xD) that there's a 50% chance to obtain either gender. So does this mean that there is no way to abuse which gender for the nidorans or fireflies that you want? Is it possible that if you hit the SAME seed that you just might end up with the OTHER gender the second, third, or fourth time?